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THE 


ORIGIN  OF  THE  FITTEST 


ESSAYS   Olf  EYOLUTIOjN" 


BY 


E.  D.  COPE,  A.  M.,  Ph.  D.  (Heidelberg) 

MEMBER  OF  THE  UNITED  STATES  NATIONAL,  ACADEMY  OF  SCIENCES  ;    CORRESPONDENT  OP 

THE  ROYAL  BAVARIAN  ACADEMY  OF  SCIENCES 


KKW  YORK 
D.    APPLETON    AND    COMPANY 

1887 


COPTKIGHT,  1S86, 

By  D.  APPLETON  AND  COMPANY. 


All  rights  reserved. 


TO  MY  FRIEND 

PROFESSOR  ALPHEUS  HYATT, 

OF   BOSTON,    MASS., 
WITH    WHOSE    STUDIES    MY    OWN    HAVE    LONG    BEEN    PARALLEL, 
AND  WITH  WHOSE   CONCLUSIONS   I   HAVE  LONG   COINCIDED, 
THIS     WORK     IS     DEDICATED 

BY 

THE    AUTHOR. 


146933 


PEEFAOE. 


The  tu^enty-one  essays  which  constitute  the  present  volume  represent 
the  reflections  which  have  suggested  themselves  to  the  author  while  engaged 
in  special  zoological  and  paleontological  studies.  While  the  original  work 
of  the  author  has  been  nearly  confined  to  the  vertebrata,  his  studies  have 
taken  in  a  wider  range.  These  have  convinced  him  that  the  conclusions 
derived  from  the  investigations  of  the  vertebrata  are  applicable  to  inverte- 
brate animals  and  to  plants. 

In  reaching  conclusions,  the  author  has  endeavored  to  avoid,  as  much 
as  possible,  any  bias  due  to  the  influence  of  any  opinions  whatsoever  on 
evolution  and  allied  subjects  which  were  already  in  the  field.  He  therefore 
avoided,  for  a  time,  reading  the  works  of  the  masters  of  the  subject,  apply- 
ing to  them  for  confirmation  or  criticism  only  after  the  publication  of  his 
own  results.  It  is  therefore  true  that  the  generalizations  contained  in  these 
essays  have  been  worked  out  by  the  author  from  such  material  as  has  come 
under  his  own  eyes,  with  little  other  aid.  It  has  also  followed  that  not  a 
few  of  the  conclusions  he  has  reached  were  not  new.  On  the  other  hand, 
some  of  the  principles  enunciated  had  not  been  clearly  stated  prior  to  the 
publication  of  these  essays.  In  some  cases  the  work  accomplished  has  con- 
sisted in  throwing  well-known  principles  into  accord  with  each  other,  as  in 
the  case  of  the  laws  of  acceleration  and  retardation. 

The  earlier  essays  are  the  more  hypothetical,  and  the  later  present  more 
numerous  demonstrations.  The  latter  have  resulted  chiefly  from  the  author's 
researches  in  the  field  of  vertebrate  paleontology,  which  have  thrown  the 
greatest  possible  light  on  the  fact  and  method  of  evolution.  For  the  his- 
tory of  this  subject  the  reader  is  referred  to  the  author's  forthcoming 
*'•  Manual  of  the  Vertebrate  Paleontology  of  North  America ''' ;  and,  for  the 
more  detailed  work,  to  the  author's  publications  in  the  "  Final  Reports  of 
the  United  States  Geological  Surveys,"  under  "Wheeler  and  Hayden,  and 
to  the  "Proceedings  of  the  American  Philosophical  Society  of  Philadel- 
phia." 

The  present  essays  are  arranged  (see  table  of  contents)  into  four  series, 
as  follows :  First,  on  General  Evolution ;  second,  on  the  Structural  Evidences 
of  Evolution ;  third,  on  Mechanical  Evolution ;  fourth,  on  Metaphysical  Evo- 
lution. In  the  first  series  the  author's  earlier  essays  are  arranged.  The 
general  principles  are  here  laid  down  or  foreshadowed.     The  essays  of  the 


vi  PREFACE. 

succeeding  sections  are  occupied  with  the  demonstration  of  these  and  other 
generaUzations,  so  far  as  practicable.  In  each  of  the  sections  some  essays 
will  be  found  to  be  more,  and  others  less,  adapted  to  popular  use.  It 
is  believed  that  the  general  reader  can  select  a  sufficient  number  of  articles 
of  minimum  technicality  to  convey  to  his  or  her  mind  a  sufficient  idea 
of  the  views  set  forth.  In  Part  I,  articles  first,  fourth,  and  sixth  are  of 
this  character.  In  Part  II,  the  first,  second,  and  third  essays  are  the 
least  technical.  In  Part  III,  the  first  article  is  the  most  popular,  although 
tbe  others  are  essential  to  an  understanding  of  the  doctrine  of  mechani- 
cal evolution.  In  Part  IV,  all  are  sufficiently  popular  for  the  reader  who 
has  some  knowledge  of  mental  science. 

A  historical  synopsis  of  the  essays  may  be  now  given.  The  attempt  is 
made  to  point  out  the  aim  of  each,  with  an  indication  of  what  may  have 
been  new  in  its  contents.  They  are  taken  up  in  the  order  of  date  of  pub- 
lication ; 

II.  The  Origin  of  Geneea.  From  the  "Proceedings  of  the  Philadel- 
phia Academy  of  Natural  Sciences  "  for  October,  1868,  and  published  sepa- 
rately by  the  author  early  in  1869.  In  this  essay  the  following  doctrines 
were  taught : 

First,  that  development  of  new  characters  has  been  accomplished  by  an 
acceleration  or  retardation  in  the  growth  of  the  parts  changed.  This  was 
demonstrated  by  reference  to  a  class  of  facts,  some  of  which  were  new,  which 
gave  ground  for  the  establishment  of  the  new  doctrine. 

Second,  that  oi  exact  parallelism  between  the  adult  of  one  individual  or 
set  of  individuals,  and  a  transitional  stage  of  one  or  more  other  individuals. 
This  doctrine  is  distinct  from  that  of  inexact  parallelism  which  had  already 
been  stated  by  von  Baer.  And  that  this  law  expresses  the  origin  of  gen- 
era and  higher  groups,  because — 

Third,  they  can  only  be  distinguished  ly  single  characters  when  all  their 
representatives  come  to  be  known. 

Fourth,  that  genera  and  various  other  groups  have  descended,  not  from 
a  single  generalized  genus,  etc.,  of  the  same  group,  but  from  corresponding 
genera  of  one  or  more  other  groups.  This  was  called  the  doctrine  of 
homologous  groups. 

Fifth,  the  doctrine  that  these  homologous  groups  belong  to  different 
geological  periods,  and. 

Sixth,  to  different  geographical  areas,  which,  therefore,  in  some  in- 
stances, are. 

Seventh,  related  to  each  other  in  a  successional  way  like  the  epochs  of 
geological  time. 

Of  these  doctrines  it  may  be  observed  that  the  first  and  second  are  now 
the  common  property  of  evolutionists,  and  are  recognized  everywhere  as 
matter  of  fact.  The  names  which  I  selected  to  express  them  have,  however, 
only  come  into  partial  use.  The  author  believes  that,  although  the  doctrine 
was  vaguely  shadowed  out  in  the  minds  of  students  prior  to  the  publication 
of  this  essay,  it  had  not  previously  been  clearly  expressed,  nor  been  reduced 


PREFACE.  ^i[ 

to  a  demonstration.  Of  the  trnth  of  the  doctrine  the  author  is  more 
than  ever  convinced,  and  he  believes  that  paleontological  discovery  lias 
demonstrated  it  in  many  instances,  and  that  other  demonstrations  will  fol- 
low. The  fourth  proposition  (that  of  homologous  groups)  is  now  held 
as  a  hypothesis  explaining  the  phylogeny  of  various  groups  of  animals. 
For  the  descent  of  one  homologous  group  from  another,  the  term  poly- 
phyletic  has  been  coined.  It  remains  to  be  seen  whether  the  doctrine 
is  of  universal  application  or  not.  That  homologous  groups  belong  to 
different  geological  horizons,  as  stated  under  the  fifth  head,  has  been 
frequently  demonstrated  since  the  publication  of  the  essay.  That  the  sixth 
proposition  is  true  in  a  certain  number  of  cases  is  well  known,  and  it 
follows  that  the  seventh  proposition  is  alsd  true  in  those  cases.  The 
latter  hypothesis,  which  was  originally  advanced  by  Prof.  Agassiz,  is,  how- 
ever, only  partially  true,  and  the  advance  of  paleontological  study  has  not 
demonstrated  that  it  has  had  a  very  wide  application  in  geological  time. 

A  proposition  which  was  made  prominent  in  this  essay  was,  that  the 
prevalence  of  non-adaptive  characters,  in  animals,  proves  the  inadequacy  of 
hypotheses  which  ascribe  the  survival  of  types  to  their  superior  adaptation 
to  their  environment.  Numerous  facts  of  this  kind  undoubtedly  indicate 
little  or  no  activity  of  a  selective  agency  in  nature,  and  do  point  to  the 
existence  of  an  especial  developmental  force  acting  by  a  direct  influence  on 
growth.  The  action  of  this  force  is  the  acceleration  and  retardation  ap- 
pealed to  in  this  paper.  The  force  itself  was  not  distinguished  until  the 
publication  of  the  essay  entitled  ''  The  Method  of  Creation  "  (No.  V),  where 
it  was  named  growth-force,  or  bathmism.  The  energetic  action  of  this  force 
accounts  for  the  origin  of  characters,  whether  adaptive  or  non-adaptive,  the 
former  differing  from  the  latter  in  an  intelligent  direction,  which  adapts 
them  to  the  environment.  The  numerous  adaptive  characters  of  animals 
had  by  that  time  engaged  the  attention  of  the  author,  and  he  found  that  they 
are  even  more  numerous  than  the  non-adaptive.  Some  of  the  latter  were  ac- 
counted for  on  the  theory  of  the  "  complementary  location  of  growth-force." 

IV.  The  Hypothesis  of  Evolution,  Physical  and  Metaphysical. 
"  Lippincott's  Magazine,"  Philadelphia,  1870 ;  reprinted  by  Charles  C.  Chat- 
field  &  Co.     New  Haven,  1870. 

This  essay  embraces  a  popular  exposition  of  the  principles  maintained  in 
the  essay  entitled  the  "  Origin  of  Genera,"  with  some  conclusions  derived 
from  the  general  facts  of  anthropology.  To  this  were  added  some  facts  in 
the  evolution  of  human  physiognomy  and  human  character,  which  had  not 
been  previously  thrown  into  harmony  with  the  laws  already  set  forth.  Un- 
fortunately, the  author  attempted  to  correlate  these  again  with  the  theories 
of  some  theologians,  and,  in  some  instances,  without  success.  A  few 
paragraphs  have  been  stricken  from  this  part  of  the  essay,  and  others  are 
allowed  to  remain  as  illustrations  of  far-reaching  hypotheses  resting  on 
little  information. 

V.  The  Method  of  Creation  of  Organic  Types.  From  the  "Pro- 
ceedings of  the  American  Philosophical  Society,"  December,  1871 ;  repub- 


viii  PREFACE. 

listed  by  McCalla  &  Stavely  the  same  year.  Read  before  the  American 
Association  for  the  Advancement  of  Science,  at  Detroit,  August  27,  1871. 
Received  the  Walker  prize  of  the  Boston  Society  of  Natural  History. 
In  this  essay  were  added  to  the  preceding,  the  following  hypotheses: 
.  1.  The  law  of  repetitive  addition,  in  which  the  structures  of  animals 
were  shown  to  have  originated  from  simple  repetitions  of  identical  ele- 
ments. 

2.  The  existence  of  an  especial  force  which  exhibits  itself  in  the  growth 
of  organic  beings,  which  was  called  growth-force,  or  bathmism, 

3.  That  development  consists  in  the  location  of  this  energy  at  certain 
parts  of  the  organism. 

4.  That  this  location  was  accomplished  by  use  or  effort,  modifying  and 
being  modified  by  the  environment;  or  the  doctrine  of  kinetogenesis. 

5.  That  the  location  of  this  energy  at  one  point  causes  its  abstraction 
from  other  points,  producing  "complementary  diminution"  of  force  at  the 
latter. 

6.  That  the  location  of  this  energy,  so  as  to  produce  the  progressive 
change  called  evolution,  is  due  to  an  influence  called  "  grade  influence." 

7.  That  inheritance  is  a  transmission  of  this  form  of  energy,  which  builds 
in  precise  accord  with  the  sources  from  which  it  is  derived. 

8.  That  this  "  grade  influence  "  is  an  expression  of  the  intelligence  of 
the  animal,  which  adapts  the  possessor  to  the  environment  by  an  "  intel- 
ligent selection." 

9.  An  attempt  to  account  for  the  origin"  of  "  mimetic  analogy "  by 
"maternal  impressions." 

On  these  propositions,  the  following  comments  may  be  made :  First, 
the  law  of  repetitive  addition  is  much  like  the  law  of  rhythm  previously  pro- 
posed by  Herbert  Spencer.*  Second,  the  force  of  growth,  or  bathmism, 
had  already  been  called  constructive  force  by  Carpenter,  who,  however, 
did  not  treat  of  its  evolutionary  or  "  grade  "  characteristics.  That  such 
force  exists  there  can  be  no  doubt  at  the  present  time,  but  it  may  be  that 
its  varied  aspects  should  each  be  considered  a  separate  species  of  force  (i.  e., 
energy).  Third,  the  relations  of  the  energetic  and  static  conditions  of  this 
force  were  considered,  but  were  not  sufficiently  followed  out  to  be  clear. 
It  is  hoped  that  greater  clearness  has  been  attained  by  the  omission  of 
a  few  paragraphs  and  the  insertion  of  an  explanatory  foot-note. 

Fourth,  that  the  location  of  this  energy  is  due  to  the  influence  of  use 
and  effort.  The  doctrine  of  the  development  of  parts  of  living  beings  by 
use,  and  their  loss  by  disuse,  is  well  known  to  have  been  put  forth  by 
Lamarck  in  1809,  who  devotes  one  of  the  longest  chapters  (No.  VII)  of  his 
"  Philosophic  Zoologique  "  to  its  discussion.  He  did  not,  however,  include 
the  element  of  efort,  prior  to  the  appearance  of  any  rudiment  of  an  organ, 
in  his  hypothesis,  which  was  proposed,  so  far  as  I  know,  for  the  first  time 
in  the  present  essay.     The  doctrine  of  use  and  disuse  has  been  sustained 


*  « 


Principles  of  Biology.'* 


PREFACE.  ix 

by  Spencer  in  his  "  Principles  of  Biology  "  as  respects  the  effect  of  motion 
on  structure  in  general,*  and  in  the  particular  case  of  the  origin  of  verte- 
brsB.t  Fifth,  the  complementary  development  of  parts  had  also  been 
pointed  out  by  Herbert  Spencer,! 

Seventh,  tlie  explanation  of  inheritance  by  the  transmission  of  the  type 
of  growth-force  possessed  by  one  generation  to  another.  This  doctrine  was 
subsequently  announced  by  Haeckel,  under  the  name  of  perigenesis,^ 
and  is  the  only  good  hypothesis  yet  proposed  for  the  explanation  of  this 
phenomenon.  Eighth,  the  theory  of  "intelligent  selection,"- or  the  agency 
of  the  intelligence  of  a  living  being  in  directing  its  movements,  and  there- 
fore its  growth,  although  a  plain  and  necessary  consequence  of  the  "  law  of 
use  and  effort,"  had  not  been,  so  far  as  I  am  aware,  announced  prior  to 
the  publication  of  this  paper.  This  important  theory  at  once  opened  the 
way  for  an  investigation  of  the  general  relations  of  mind  to  evolution,  which 
involved  the  question  of  the  origin  and  development  of  mind  itself.  These 
questions  were  more  fully  discussed  in  the  papers  of  Part  IV,  on  "  Metaphys- 
ical Evolution."  Ninth,  the  origin  of  mimetic  analogy.  The  explanation 
offered  is  almost  necessary,  if  the  doctrine  of  the  influence  of  effort  on  struct- 
ural growth  be  true. 

I.  Evolution  and  its  Consequences,  From  the  *'  Penn  Monthly  Maga- 
zine," Philadelphia,  for  May,  July,  and  August,  1872, 

This  is  a  popular  exposition,  with  elaboration,  of  the  doctrines  contained 
in  the  preceding  essays.  The  evolution  of  mind  is  more  fully  stated,  the 
hypothesis  adopted  being  that  proposed  by  Spencer  in  his  "  Principles  of 
Psychology,"  published  in  1855. 

VII.  The  Homologies  and  Origin  of  the  Types  of  Molar  Teeth 
OF  THE  Mammalia  Edtjcabilia.  From  the  "  Journal  of  the  Academy  of 
Natural  Sciences,"  Philadelphia,  March  30,  1874. 

The  object  of  this  paper  was  to  show  that  the  various  more  or  less  com- 
plex types  of  molar  "teeth  displayed  by  the  Ungulate  Mammalia  are  referable 
to  modifications  of  a  primitive  quadituberciilar  type,  from  which  they  were 
supposed  to  have  been  descended.  The  histories  and  homologies  of  the 
carnivorous  dentitioa  were  not  included  in  this  paper.  In  order  to  com- 
plete the  subject,  I  have  inserted  brief  notes  of  the  conclusions  I  have  since 
attained  in  this  field  :  first,  as  to  the  type  of  inferior  sectorial  teeth,  in  1875  ; 
and,  second,  as  to  the  superior  molars,  in  1883. 

At  the  end  of  the  paper  a  similar-  comparison  between  the  feet  of  the 
same  type  of  mammals  is  made,  and  general  conclusions  reached  in  the  fol- 
lowing language :  "  I  trust  that  I  have  made  it  sufiiciently  obvious  that  the 
primitive  genera  of  this  division  of  mammals  [Mammalia  Educabilia  =  Un- 
guiculata  and  Ungulata  sensu  lata]  must  have  been  bunodonts  with  penta- 
■daetyl  plantigrade  feet." 


Vol.  ii,  p.  167.  t  Vol.  ii,  p.  195.  X  "  Principles  of  Biology." 

*  See  Ryder,  "American  Naturalist,"  January,  1879. 


X  PREFACE. 

The  nearest  approaches  to  a  similar  anticipation  on  the  part  of  other 
naturalists,  which  I  have  been  able  to  find,  refer  to  the  number  of  toes  only, 
and  are  of  restricted  application.  Thus  Kowalevsky  remarks  ("  Monographie 
der  Gattung  Anthracotherium,  Palaeontographica,"  xxii,  p.  1452) :  "•  So  we 
can  assume  a  tetradactyl  foot  as  our  point  of  departure,  although  it  can 
not  have  the  least  effect  on  the  result  in  case  the  original  ungulate  foot 
should  have  been  pentadactyl.  If  I  have  set  out  with  a  tetradactyl  foot 
it  is  simply  because  I  wish  to  adhere  so  far  as  possible  to  facts."  This  was 
written  August,  1873,  but  how  soon  thereafter  it  was  printed  I  do  not  know. 
I  did  not  meet  with  it  until  at  least  a  year  after  the  publication  of  my  paper 
of  March,  1874,  cited.  Secondly,  Marsh,  in  writing  on  the  genealogy  of 
the  horses  ("American  Journal  of  Science  and  Arts,"  March,  1874,  p.  257), 
says :  "  A  still  older  ancestor  [of  the  horse],  possibly  in  the  Cretaceou?, 
doubtless  had  five  toes  on  each  foot,  the  typical  number  in  mammals."  My 
paper  was  published  during  the  same  month  as  the  above;  but  I  communi- 
cated the  substance  of  the  generalization  in  question  to  the  Philadelphia 
Academy  the  day  it  was  read,  November  18,  1873,  which  was  published  in 
the  "Proceedings  of  the  Society,"  January  13,  1874,  p.  2. 

XYIII.  Consciousness  in  Evolution.  From  the  "  Penn  Monthly  Maga- 
zine," Philadelphia,  July,  1875. 

In  this  paper  the  doctrine  of  intelligent  selection  is  analyzed,  and  the 
problem  reduced  to  its  essential — the  relations  of  consciousness  to  matter. 
The  doctrine  of  the  origin  of  reflex  and  automatic  acts  from  conscious  states, 
or  archaesthetism,  is  here  first  proposed.  From  the  characters  of  proto- 
plasm the  inference  is  derived  that  that  substance  is  not  necessarily  the  only 
one  capable  of  supporting  consciousness.  The  author  is  not  aware  of  any 
previous  attempt  to  render  these  propositions  probable. 

VIII.  The  Relation  of  Man  to  the  Teetiaey  Mammalia.  From  the 
"  Penn  Monthly  Magazine,"  December,  1875.  Read  before  the  American 
Association  for  the  Advancement  of  Science,  at  Detroit.' 

The  fact  that  the  hard  tissues,  and  probably  the  digestive  system,  of  man, 
are  constructed  on  the  type  of  the  Mammalia  of  the  early  Eocene  period 
is  here  pointed  out  for  the  first  time. 

III.  The  Theoey  of  Evolution.  Remarks  made  before  the  Academy 
of  Natural  Sciences  of  Philadelphia,  February  22,  1876,  and  published  in  the 
"Proceedings  of  the  Society,"  1876,  p.  15. 

These  remarks  exhibit  the  correspondence  between  the  evolutionary 
systems  of  Haeckel  and  of  the  writer,  and  combine  them  into  a  symmetricid 
whole. 

XXI.  The  Oeigin  of  the  Will.  From  the  "Penn  Monthly  Magazine," 
Philadelphia,  June,  1877. 

In  this  paper  the  attempt  is  made  to  render  the  existence  of  freedom  of 
will  probable  by  a  process  of  argument,  and  also  to  demonstrate  its  exist- 
ence by  another  kind  of  argument.  As  is  well  known,  there  are  two  op- 
posed doctrines  respecting  this  important  question.  One  of  these,  which 
has  by  far  the  larger  number  of  adherents,  is  that  the  human  mind  embraces 


PREFACE.  xi 

among  its  powers  a  freedom  of  will,  or  spontaneity  in  action.  The  other 
view  is,  that  there  is  no  such  power,  but  that  the  actions  are  merely  the 
necessary  result  of  the  strongest  pressure  of  the  strongest  inducement  or 
motive.  The  doctrine  of  evolution  is  known  to  lend  support  to  the  latter 
doctrine.  In  the  present  paper  the  attempt  is  made  to  prove  that  free  will 
is  a  new  power  which  supervenes  on  the  process  of  evolution.  This  is  done 
by  assuming  the  existence  of  a  class  of  acts  for  which  the  term  altruistic  is 
retained,  which,  undoubtedly,  would  require  freedom  for  their  perform- 
ance. The  only  question  here  is,  whether  there  be  any  such  class  of  acts  as 
are  defined  under  the  above  name  in  this  essay.  If  tliere  be  no  such  class 
of  acts,  the  demonstration  based  on  it  falls  to  the  ground ;  and  the  author 
is  xiot  at  present  sure  whether  there  be  such  a  class  of  acts  or  not. 

The  argument  by  which  freedom  of  will  is  rendered  probable  is  not 
open  to  any  serious  objection,  and  rests  on  the  necessity  for  action  which 
sometimes  arises  in  cases  where  there  is  no  experience  or  knowledge  to  serve 
as  a  determining  motive  or  power.  These  cases  are  supposed  to  involve 
moral  questions.  The  doctrine  is  then  intermediate  between  the  two  oppos- 
ing ones  which  have  long  divided  the  world  of  thought,*  It  permits  of  the 
development  of  a  free  will  in  previously  automatic  beings,  as  a  phenomenon 
superposed  on  mental  evolution.  The  argument  demonstrates  nothing  more 
tlian  that  freedom  is  possible;  a  conclusion  which  is,  however,  important, 
since  it  shows  that  the  position  of  the  determinists  is  not  impregnable, 

XII.  The  Relation  of  Animal  Motion  to  Animal  Evolution.  From 
"  The  American  Naturalist,"  January,  1878.  Read  before  the  American 
Association  for  the  Advancement  of  Science,  at  Nashville,  August,  1877. 

The  effects  of  the  actions  of  animals  on  their  structure  are  considered, 
as  in  previous  papers,  and  especial  attention  is  paid  to  the  influence  of  ani- 
mals in  the  changes  they  produce  in  their  environment.t 

XI Y.  The  Origin  of  the  Specialized  Teeth  of  the  Carnivoea.  From 
"  The  American  Naturalist,"  March,  1879. 

The  mechanical  reasons  for  the  changes  in  the  dentition  of  carnivorous 
mammals  during  geologic  time  are  pointed  out  for  the  first  time. 

VI.  A  Review  of  the  Modern  Doctrine  of  Evolution.  From  "The 
American  Naturalist,"  March  and  April,  1880.  A  lecture  delivered  before 
the  California  Academy  of  Sciences,  October  27,  1879.  It  is  a  general 
synopsis  of  views  presented  in  preceding  papers. 

XY.  On  the  Origin  of  the  Foot-Structure  of  the  Ungulates. 
From  "  The  American  Naturalist,"  April,  1881. 

This  essay  embraces  an  explanation  of  the  cause  of  the  diminution  of  the 
number  of  digits  in  the  diplarthrous  ungulate  mammals ;  of  the  reasons 
why  some  are  even-  and  some  odd-toed ;  and  of  the  origin  of  some  of  the 


*  This  view  is  adopted  by  President  Xoah  Porter  in  one  of  his  latest  metaphysi- 
cal works. 

f  A  synopsis  of  the  relations  of  animals  to  their  environment  is  given  by  Spen- 
cer, "  Principles  of  Biology,"  vol.  i,  p.  466. 


xii  PREFACE. 

articulations  of  the  tarsus.     These  explanations,  so  far  as  based  on  paleonto- 
logical  grounds,  were  new  at  the  time. 

XVI.  The  Effect  of  Impact  and  Steains  on  the  Feet  of  Mammalia. 
From  "  The  American  Naturalist,"  July,  1881. 

The  origin  of  the  structures  of  all  the  articulations  of  the  limbs  of  all  the 
Mammalia  are  explained  as  the  effects  of  impacts  and  strains.-  The  demon- 
stration is  based  largely  on  paleontological  evidence,  and  is  new. 

XIX.  On  Aechaesthetism.  From  "  The  American  Naturalist,"  June, 
1882. 

This  doctrine  is  discussed  and  illustrated  on  the  basis  laid  down  in  the 
essay  "  Consciousness  in  Evolution,"  and  a  classification  of  theories  of  crea- 
tion is  presented. 

IX.  The  Developmental  Significance  of  Human  Physiognomy.  From 
"The  American  Naturalist,"  June,  1883. 

In  this  paper  suggestions  presented  in  Art.  IV,  entitled  "The  Hypothe- 
sis of  Evolution,  Physical  and  Metaphysical,"  are  developed,  and  the  physical 
significance  of  the  form-characters  of  men  in  general  are  considered.  Noth- 
ing except  reference  to  a  few  leading  points  of  the  subject  had  been  pub- 
lished prior  to  this  paper,  so  far  as  the  author  has  been  able  to  discover.  In 
connection  with  a  paper  on  the  "Evolutionary  Significance  of  Human  Char- 
acter," a  foundation  was  laid  for  a  scientific  physiognomy. 

X.  The  Evidence  foe  Evolution  in  the  Histoey  of  the  Extinct 
Mammalia.  A  lecture  delivered  before  the  American  Association  for  the 
Advancement  of  Science,  at  Minneapolis,  August,  1883. 

In  this  paper  are  collected  the  evidences  of  descent  displayed  by  the 
Mammalia  (and  in  one  instance  by  the  Batrachia),  as  derived  from  the  pale- 
ontological researches  of  the  author.  These  had  been  in  some  points  fore- 
shadowed in  the  author's  memoir  on  the  homologies  and  origin  of  the  struct- 
ure of  the  molar  teeth  in  the  Mammalia  Educabilia  in  1874,  which  were 
here  shown  to  have  been  realized  by  subsequent  discovery,  and  a  number 
of  other  evidences  added.  Restatements  of  the  laws  of  kinetogenesis,  and 
of  the  origin  of  morals,  were  made. 

XVII.  The  Evolutionaey  Significance  of  Human  Chaeactee.  From 
the  "  American  Naturalist,"  September,  1883, 

The  characters  of  the  adult  mind  are  compared  with  those  of  the  child, 
and  with  those  of  the  lower  animals,  and  the  direction  of  their  evolution 
pointed  out.  Most  of  the  propositions  contained  in  this  paper  were  new  at 
the  time  of  its  publication. 

XIII.  The  Teituberculae  Type  of  Molae  Teeth  in  the  Mammalia. 
From  the  proceedings  of  the  American  Philosophical  Society,  1883,  page 
324;*  published  in  advance  in  the  "Paleontological  Bulletin,"  No.  37, 
January  2,  1884. 

The  origin  of  the  ungulate  molar  tooth  had  already  been  traced  to  a 
quadritubercular  type  in  paper  No.  VII  (March  and  January,  1874).     The 

*  Not  published  until  1884. 


PREFACE.  xiii 

present  paper  shows  that  this  type  in  the  upper  jaw  is  a  derivative  of  a  tri- 
tubercular  type,  while  that  of  the  lower  jaw  is  a  derivative  of  a  quinquetu- 
bercular  type,  or  a  tritubercular  type  with  a  heel,  which  may  support  two 
additional  tubercles.  The  tritubercular  type  was  again  traced  to  the  sim- 
ple cone.     This  generalization  was  new  at  the  time  of  publication. 

XX.  Catagenesis.  Vice-presidential  address  delivered  before  the  bio- 
logical section  of  the  American  Association  for  the  Advancement  of  Sci- 
ence, Philadelphia,  September  4,  1884. 

The  hypothesis  of  catagenesis  which  is  put  forth  in  this  paper  teaches 
that  primitive  energy  was  and  is  conscious,  and  that  all  unconscious  forms 
of  energy,  whether  "vital"  or  non-vital,  have  been  derived  from  it  by  a 
process  of  retrograde  metamorphosis.  The  first  stage  of  this  retrogression 
is  the  loss  of  consciousness,  or  cryptopnoy.  Evidence  for  this  kind  of  meta- 
morphosis is  derived  from  every-day  experience,  and  from  the  designed 
character  of  automatic  acts.  That  a  form  of  energy  is  conscious  is  inferred 
from  the  nature  of  designed  conscious  acts  of  animals.  The  author  had  not 
met  with  any  scientific  statement  of  this  theory  prior  to  the  preparation  of 
this  lecture. 

XI.  The  Evolution  of  the  Yeetebeata,  Progeessive  and  Reteo- 
GEESsivE.  From  the  "American  Naturahst,"  February,  March,  and  April, 
1885. 

This  paper  sets  forth  the  results  of  paleontological  investigation  of  the 
Vertebrata,  in  a  series  of  phylogenies.  These  are,  first,  the  phylogeny' 
of  the  classes ;  then  the  special  phylogenies  of  their  contents  or  of  the 
orders.  Here  are  introduced  the  newly-discovered  relations  of  the  Anti- 
archa  and  the  Ichthyotomi  to  the  fish-like  vertebrates,  and  of  the  thero- 
morphous  reptiles  to  the  Mammalia.  Also,  the  ancestral  relation  of  the 
Theromorpha  to  most  other  reptiles,  and  of  the  Condylarthra  to  the  placental 
Mammalia,  and  to  man.  Many  of  the  other  results  set  forth  in  this  essay 
are  derived  from  the  paleontological  researches  of  the  author.  Some  of 
them,  especially  the  lemurine  (condylarthrous)  ancestry  of  the  placental 
Mammalia,  had  been  anticipated  on  theoretical  grounds  by  Haeckel  in  his- 
"  History  of  Creation  "  ("  Schopfungsgeschichte  ").  Haeckel  was  very 
general  in  his  proposition,  and  did  not  anticipate  the  details  of  the  demon- 
stration. My  investigations  enabled  me  to  produce  these,  which  bring  out 
in  a  striking  manner  the  sagacity  of  Prof,  Haeckel.  I  consider  further  the 
question  of  degeneracy,  and  the  significance  of  the  phylogeny  with  refer- 
ence to  this  subject  is  pointed  out. 

In  conclusion,  it  may  be  said  that  the  principal  object  which  the  author 
set  before  him,  in  the  studies  here  recorded,  has  been  the  discovery  of 
the  laws  of  variation,  or  of  the  "  Origin  of  the  Fittest."  These  essays 
express  the  light  which  he  has  been  able  to  obtain  on  this  difficult  question 
up  to  the  present  time.  The  results  could  be  better  and  more  briefly  pre- 
sented in  a  systematic  form,  but  the  author  reserves  this  for  a  future  occa- 
sion. 


COH'TENTS. 


PART   I.— GENERAL  EVOLUTION. 

L — Evolution  and  its  Consequences 

IL — The  Origin  of  Genera 

in. — The  Theory  op  Evolution 

IV. — The  Hypothesis  op  Evolution,  Physical  and  Metaphysical 

V. — The  Method  of  Creation  of  Organic  Forms   . 
VI. — Review  of  the  Modern  Doctrine  of  Evolution 


PAGB 

1 
41 

124 
128 
173 

215 


PART   IL— STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

VII. — The  Homologies  and  Origin  of  the  Types  op  Molar  Teeth  of  the 

Mammalia  Educabilia 241 

VIII. — The  Relation  of  Man  to  the  Tertiary  Mammalia  .         .         .  268 

IX. — The  Developmental  Significance  op  Human  Physiognomy      .        .  281 
X. — The    Evidence    for    Evolution   in    the    History   of   the   Extinct 

Mammalia 294 

XI. — The   Evolution  of  the  Vertebrata,  Progressive  and   Retrogres- 
sive    314 

PART  IIL— MECHANICAL  EVOLUTION. 

XII. — The  Relation  of  Animal  Motion  to  Animal  Evolution  .         .  350 

XIII. — On  the  Trituberculate  Tooth  in  the  Mammalia    ....  359 

XIV. — The  Origin  of  the  Specialized  Teeth  of  the  Carnivora       .        .  363 

XV. — The  Origin  of  the  Foot  Structures  of  the  Ungulates         .        .  368 

XVI. — The  Effect  of  Impacts  and  Strains  on  the  Feet  of  Mammalia    .  373 


xvi  COITTEN'TS. 

PART  IV.— METAPHYSICAL  EVOLUTION. 

PAGE 

XVII. — The  Etolutionary  Significance  of  Human  Character          .        .  378 

XVIIL — Consciousness  in  Evolution 390 

XIX. — Arch>esthetism 405 

XX. — Catagenesis 422 

XXI.— The  Origin  of  the  Will 437 


LIST   OF   ILLUSTEATIOI^S. 


Plates. 

PLATE  PAGE 

I.  Figures  and  Diagrams  of  the  Circulatory  Centers  of  Vertebrata.    Copied 

from  Gegenbaur  and  His,  mostly  enlarged 60 

II  and  Ila.  Figures  of  Lizards  of  the  families  Iguanidae  and  Agamidae 

compared 9*7 

III  and  Illa.  Mimetic  analogy  in  the  colors  and  patterns  in  snakes  of  dif- 
ferent genera  and  species 105 

ly  and  V.  Series  of  Crania  of  Different  Families  of  Tailless  Batrachia 

showing  similar  stages  of  development.     Original     .         .         .  220,  221 

Explanation 222 

VI.  Succession  of  Modifications  of  Feet  of  Diplarthrous  Ungulata.    Original  271 
VII.  Succession  of  Dental  Forms,  mostly  of  LTngulata.    From  Gaudry,  Wort- 
man,  and  Cope 275 

VIII.    Uintatherium  eornutvm  Cope,  restored,  one  twenty-seventh  natural  size. 

From  Cope,  Marsh,  and  Osbom 277 

IX.  Anaptomorphus  and  Homo ;  Cranium,  Brain,  and  Teeth.     Original,  ex- 
cept Figs.  8  and  9  from  Allen 279 

X.  Esequibo  Indians.     From  photographs  by  Endlich        ....  286 

XI.  The  Wrestler.     From  the  Vatican        .        .  ....  289 

XII.  Venus  of  the  Capitol 292 

XIII.  Phenacod^is  primcevus  Cope,  Skeleton  as  found  in  matrix,  one  seventh 

natural  size.     Original      .........  300 

XIV.  Brains  of  Extinct  Mammalia.     Original,  except  Fig.  2  from  Marsh        .  308 
XV.  Diclonius  mirabilis,  Skull  Profile.     Original 338 

XVI.  Diclonius  mirabilis,  Skull  from  below,  one  half  the  mandible  removed .  339 
XVII.  Phenacodus  vortmani,  Skeleton  as  found  in  Matrix,  two  ninths  natural 

size.     Original 345 

XVIII.  Hycenodon  horridus  Leidy,  Skull  one  half  natural  size.     From  Lcidy     .  364 


Wood-Cuts. 

FIG. 

1.  Diagram  illustrating  acceleration  and  retardation 10 

2.  Diagram  illustrating  relations  of  genera  of  batrachia  anura  .  .  .80 
3  to  6.  Diagrams  illustrating  development  of  genera  of  batrachia  anura  .  81 
7.  Same  as  Fig.  1    .        , 1*76 


XVlll 


LIST  OF  ILLUSTRATIONS. 


FIG. 

8.  Sternum  and  adjacent  parts  of  Scaphiopus  Jiolbrooki  .... 

9.  Sternum  of  Tadpole  of  Rana  temporaria    ...... 

10.  Sternum  of  adult  Rana  temporaria     ....... 

11.  Metacarpus,  carpus,  and  distal  extremity  of  radius  of  Poehroiherium  vihoni 

12.  The  same,  less  radius,  with  first  phalanges  of  Procamelus  occidentalis 

13.  Skull  of  Protolahis  transmontanus 

14.  Skull  of  Procamelus  occidentalis . 

15.  Tooth  of  Globicephalus       .... 

16.  Tooth  of  Jaculus  hudsonicus 

17.  Tooth  of  Leploch(e7'us  spectabilis.     From  Leidy 

18.  Tooth  of  Rhinocerus,  milk  superior  molar  . 

19.  Tooth  of  Achcenodon  insolens 

20.  Tooth  of  Hippopotamus  amphibius.     From  Cuvier 

21.  Tooth  of  Hyopotamu^  velaunus.     From  Blainville 
2 1.  Tooth  of  Hyopotamus  americanus.     From  Leidy 

23.  Tooth  of  Procamelus  robustus.     From  Leidy 

24.  Tooth  of  Merychyus  major.     From  Leidy    . 

25.  Tooth  of  Tapirus       ..... 

26.  Tooth  of  Mastodon  angustidois.     From  Cuvier 

27.  Tooth  of  Mastodon  americanus.     From  Cuvier 

28.  Tooth  of  Dinotherium.     From  Cuvier 

29.  Tooth  of  Elephas  indicus.     From  Cuvier     . 

30.  Tooth  of  Microsyops  elegans.     From  Leidy 

31.  Tooth  of  Hyopsodus  paulus.     From  Leidy  . 

32.  Tooth  of  Palceosyops  kevidens.     From  Leidy 

33.  Tooth  of  Ancldppodus  riparius.     From  Leidy 

34.  Tooth  of  Palceosyops  vallidens.     From  Leidy 

35.  Tooth  of  Pcdceotherium.     From  Cuvier 

36.  Tooth  of  Hipposyus.     From  Leidy 

37.  Tooth  of  Hipposyus  more  worn.     From  Leidy 

38.  Tooth  of  Hypohippus.     From  Leidy   . 

39.  Tooth  of  Equus,  superior  molar.     From  Leidy 

40.  Tooth  of  Equus,  inferior  molar.     From  Leidy 

41.  Tooth  of  Baihmodon  radians 

42.  Tooth  of  Uintatherium  robustum,  superior  molar. 

43.  Tooth  of  Uintatherium.  robustum^  inferior  molar. 

44.  Periptychus  rhabdodon,  part  of  posterior  foot 

45.  Coryphodon  elcphantopus,  right  fore  foot,  one  third  natural  size 

46.  Coryphodon  elephantopus^  right  posterior  foot     . 

47.  Phenacodus  primcevus,  right  anterior  foot,  one  third  natural  size, 

48.  Phenacodm  primcevus^  left  posterior  foot,  one  third  natural  size 

49.  Homo  sapiens^  left  anterior  foot  (hand),  one  third  natural  size     . 

50.  Homo  sapiens.,  left  posterior  foot,  one  third  natural  size 

51.  Phenacodus  primcevus  Cope,  skull,  one  third  natural  size,  from  below 

52.  Simia  satyrus,  section  of  skull  of  adult       ..... 
52a.  Simia  satyrus,  section  of  skull  of  young   ...... 

53.  Homo  sapiens,  infant  at  term     .         .         ..... 


From  Leidy 
From  Leidy 


PAGE 

.  217 
.  217 
.  217 
.  219 
.  219 
.  223 
.  223 
.  243 
.  243 
.  243 
.  244 
.  253 
.  254 
.  254 
.  254 
.  254 
.  255 
.  255 
.  256 
.  256 
.  256 
.  256 
.  257 
.  257 
.  257 
.  257 
.  257 
.  258 
.  258 
.  258 
.  258 
.  259 
.  259 
.  260 
.  260 
.  260 
.  268 
.  269 
.  269 
.  270 
.  270 
.  272 
.  272 
.  273 
.  283 
.  283 
.  284 


LIST   OF  ILLUSTRATIONS. 


XIX 


PIG. 

54. 
55. 
56. 
57. 

58. 

59. 

60. 

61. 
62. 
63. 
64. 

65.' 

66. 

67. 

68. 

69. 

70. 

71. 

72. 

73. 

74. 

75. 

76. 

77. 

78. 

79. 

80. 

81. 


,  PAGE 

Homo  sapiens^  portrait  of  girl  at  five  years  .         .         .         .         .        .  285 

Homo  sapiens^  portrait  of  same  at  seventeen  years 285 

Homo  sapiens,  portrait  of  Luchatze  negro  woman        .....  287 

Homo  sapiens,  portrait  of  Luchatze  negro  woman 287 

Homo  sapiens,  portrait  of  Satanta,  chief  of  the  Kiowa  Indians  of  Xoith 

America 288 

An  Australian  native 291 

Eryops  megacephabu,  a  batrachian  of  the  Permian  epoch  of  Texas  ;  vertebral 

column 804 

Sleeve  of  coat,  showing  folds 305 

Bothriolepis  canadensis,  from  above    ........  323 

Chelyosoma  maclovianiim,  a  tunicate  from  Point  Barrow,  Alaska,  from  above  S23 
Stypolovhus  whitice,  skull  and  dentition,  displaying  the  tritubercular  type  of 


molars   ...... 

' Deltatherium  fundaminis,  skull,  profile 
Oxycena  lupina,  jaws  and  teeth  . 
Procehcrtts  julieni,  skull.     From  Filhol 
Dinictis  cyclops,  skull 
Smilodon  neoffceics,  skull 
CorypJiodon  elephantopus,  hind  foot  above 

Aphelops  megalodus,  hind  tarsus  and  metatarsus,  from  front  and  above 
Proiohippus  sejunctus,  posterior  foot,  front 
Po'ehrotherium  labiatum,  posterior  foot,  front 
Poebrotherium  vilsoni,  carpus,  metacarpus,  and  end  of  radius,  from^  front 
Amhlydonus  sinosus,  a  creodont ;  distal  end  of  tibia 
Oxycena  m,orsitans,  a  creodont ;  distal  end  of  tibia 
ArchcBlurus  dehilis,  an  extinct  cat ;  distal  end  of  tibia, 
Nimravus  gomphodus,  a  cat ;  femur  . 
Procamelus  occidentalis,  part  of  fore  foot 
Cosoryx  furcatus,  part  of  fore  foot 
Poebi'oiherium  vilsoni,  part  of  fore  foot 


with  astragalus 


360 
362 
365 
366 
306 
367 
369 
369 
370 
370 
371 
375 
375 
375 
375 
376 
376 
376 


PART  I. 

GENERAL    EYOLUTIOK 


I. 

EVOLUTION  AND   ITS   CONSEQUENCES. 

The  broad  theory  of  evolution  includes  the  theories  of  devel- 
opment of  the  solar  system  and  its  members,  as  expressed  by  the 
nebular  hypothesis  ;  the  theory  of  development  of  life  by  molecu- 
lar movements  consequent  upon  certain  combinations  of  non-living 
matter ;  and,  lastly,  the  theory  of  development  of  the  species  of 
animals  and  plants  by  descent,  the  later  from  the  earlier,  with 
accompanying  change  of  form  and  character.  It  attempts  noth- 
ing less  than  a  history  of  the  process  of  creation  of  the  universe, 
so  far  as  we  can  behold  it ;  and  is,  therefore,  an  attempt  to  formu- 
late the  plans  and  thoughts  of  the  Author  of  that  universe. 
Hence,  it  is  not  surprising  that  it  excites  the  interest  of  the  best 
of  men,  especially  as  it  is  one  of  the  results  of  the  efforts  of  a 
class  of  these,  crowning  many  centuries  of  labor  and  thought. 

The  object  of  the  present  essay  is  to  discuss  familiarly  the 
latter  of  these  theories  of  evolution,  viz.,  that  respecting  the 
si3ecies  of  animals  and  plants.  As  all  are  aware,  this  mode  of 
accounting  for  the  creation  of  organized  beings  has  attained 
especial  prominence  at  the  present  time,  and  possesses  more  of 
interest  to  most  readers  because  of  its  explanation  of  our  own 
origin.  Moreover,  it  rests  on  more  indubitable  evidence  than  the 
two  other  theories.  The  constitution  and  arrangement  of  the 
members  of  the  solar  system  point  to  their  origin  by  derivation 
from  primal  masses  of  vaporous  matter  through  the  mutual  opera- 
tion of  the  ordinary  laws  of  attraction  and  motion.  The  position- 
ing is  precisely  as  it  should  be  had  such  process  taken  place,  but 
the  process  itself,  that  is,  the  change  from  type  to  type  of  celes- 
tial body,  has  not  been  observed. 
I 

D.  H.  HILL  LIBRARY 
North  Carolina  State  Colteg« 


2  GENERAL  EVOLUTION. 

The  case  is  far  diCerent  with  the  theory  as  regards  organized 
or  living  beings.  Not  only  are  the  mutual  relations  of  animals 
and  plants  to  each  other  such  as  should  have  resulted  from  a  de- 
scent or  development,  but  the  changes  from  type  to  type  have 
been  actually  observed,  and  in  sufficient  number  to  place  the 
hypothesis  on  the  basis  of  ascertained  fact,  as  referring  to  a  cer- 
tain range  of  objects — say,  in  the  case  of  the  animal  kingdom,  to 
individuals  distinguished  by  structural  characters  within  the  range 
of  each  of  the  three  to  six  great  primary  divisions  or  "  branches." 

There  are  two  totally  distinct  propositions  involved  in  this 
question,  which  are  confounded  by  the  general  public,  and  not 
unfrequently  by  students  and  writers  on  it.  These  are,  first,  the 
evidence  which  seems  to  prove  that  this  evolution  has  taken  place  ; 
secondly,  the  evidence  as  to  the  nature  of  the  laws  of  its  progress. 
A  want  of  constant  distinction  between  these  views  of  the  case 
has  greatly  obscured  it  and  injured  the  evidence  on  one  side  or 
the  other. 

The  evidence  in  favor  of  evolution  is  abundant,  and  is  cited 
in  fragments  by  various  contemporary  writers,  foremost  among 
whom,  both  in  time  and  abundance  of  writings,  comes  Charles 
Darwin. 

Much  less  has  been  done  in  explanation  of  the  laws  of  evo- 
lution. Darwin  and  his  immediate  followers  have  brought  out 
the  law  of  ^^ natural  selection";  Spencer  has  endeavored  to  ex- 
press them  in  terms  of  force;  while  Hyatt,  Cope,  Packard,  and 
others  have  advanced  the  law  of  "acceleration  and  retardation." 

In  earlier  days,  when  information  was  distributed  slowly  and 
books  were  few,  it  was  long  before  any  new  truth  or  doctrine 
reached  the  majority  of  people,  still  less  was  adopted  by  the  rul- 
ing classes.  But  the  modern  theory  of  evolution  has  been  sjDread 
everywhere  with  unexamjoled  rapidity,  thanks  to  our  means  of 
printing  and  transportation.  It  has  met  with  remarkably  rapid 
acceptance  by  those  best  qualified  to  judge  of  its  merits,  viz.,  the 
zoologists  and  botanists,  while  probably  a  majority  of  the  public, 
in  this  region  at  least,  profess  to  reject  it.  This  inconsistency  is 
due  to  two  principal  causes.  In  the  first  place,  Darwin's  demon- 
stration contained  in  the  "  Origin  of  Species  "  extends  little  fur- 
ther than  as  stated  in  the  title  of  his  work.  He  proves  little  more 
than  that  species  of  the  same  genus  or  other  restricted  groups 
have  had  a  common  origin  ;  and,  further,  his  theory  of  natural 
selection  is  to  the  plainest  understanding  incomplete  as  an  ex- 


EVOLUTION"   AND   ITS   CON-SEQUENCES.  3 

planation  of  their  ''origin/'  as  its  author  indeed  freely  allows. 
Besides,  the  unscientific  world  is  particularly  unreasonable  on 
one  point.  Little  knowing  the  slow  steps  and  laborious  effort  by 
which  any  general  truth  is  reached,  they  find  in  incompleteness 
ground  of  condemnation  of  the  whole.  Science  is  glad  if  she  can 
prove  that  the  earth  stands  on  an  elephant,  and  gladder  if  she  can 
demonstrate  that  the  elephant  stands  on  a  turtle ;  but,  if  she  can 
not  show  the  support  of  the  turtle,  she  is  not  discouraged,  but 
labors  patiently,  trusting  that  the  future  of  discovery  will  justify 
the  experience  of  the  past. 

If,  then,  some  of  the  people  find  Mr.  Darwin's  argument  in- 
complete, or  in  some  points  weak,  it  may  be  answered,  so  do  the 
student  classes,  who,  nevertheless,  believe  it.  This  is  largely  be- 
cause Darwin's  facts  and  thoughts  repeat  a  vast  multiplicity  of 
experiences  of  every  student,  which  are  of  as  much  significance 
as  those  cited  by  him,  and  which  only  required  a  courageous 
officer  to  marshal  them  into  line,  a  mighty  host,  conquering  and 
to  conquer.  These  will  slowly  find  their  way  into  print,  some  in 
one  country  and  some  in  another. 

I.    THE   FACT   OF   EVOLUTION". 

As  to  the  truth  of  the  theory,  the  proof  has  been  stated  in 
more  than  one  form.  The  first  and  simplest,  and  essentially  the 
central  argument  of  Darwin,  is  as  follows  : 

In  every  family  or  larger  group  of  animals  and  plants  there 
exists  one  or  more  genera  in  which  the  species  present  an  aggre- 
gation of  specific  intensity  of  form ;  that  is,  that  species  become 
more  and  more  closely  related,  and  finally  varieties  of  single  spe- 
cies have  to  be  admitted  for  the  sake  of  obtaining  a  systematic 
definition  or  ''  diagnosis,"  which  will  apply  to  all  the  individuals. 
These  varieties  are  frequently  as  well  marked  as  the  nearly-related 
species,  so  far  as  amount  of  difference  is  concerned,  the  distinc- 
tion between  the  two  cases  being  that  in  the  varieties  there  is  a 
gradation  from  one  to  the  other  ;  in  the  species,  none.  Neverthe- 
less, between  some  of  the  varieties  transitions  mav  be  of  rare  oc- 
currence,  and  in  the  case  of  the  ''species"  an  intermediate  indi- 
vidual or  two  may  occasionally  be  found.  Thus  it  is  that  differ- 
ences, called  varietal  and  specific,  are  distinguished  by  degree 
only,  and  not  in  kind,  and  are,  therefore,  the  results  of  the  opera- 
tion of  uniform  laws.  Yet,  according  to  the  old  theory,  the  varie- 
ties have  a  common  origin,  and  the  species  an  independent  one ! 


« 


4  GENERAL  EVOLUTION. 

To  find  examples  of  what  is  asserted,  it  is  only  necessary  to  refer 
to  the  diagnostic  tables  and  keys  of  the  best  and  most  honest 
zoologists  and  botanists.  It  is  true  that  these  diagnoses  are  dry 
reading  to  the  non-professional,  yet  they  embrace  nearly  all  that  is 
of  value  in  this  part  of  biological  science,  and  must  be  mastered  in 
some  department  before  the  student  is  in  possession  of  the  means 
of  forming  an  opinion.  The  neglect  to  do  this  explains  why  it  is 
that,  after  all  that  has  been  written  and  said  about  protean  spe- 
cies, etc.,  the  subject  should  be  so  little  understood. 

It  is  true  that  in  but  few  of  these  cases  have  the  varieties  been 
seen  to  be  bred  from  common  parents,  a  circumstance  entirely 
owing  to  the  difficulties  of  observation.  The  reasoning  derived 
from  the  relations  of  differences  appears  to  be  conclusive  as  to 
their  common  origin,  unless  we  are  prepared  to  adopt  the  oppo- 
site view,  that  the  varieties  have  originated  separately.  As  these 
avowedly  grade  into  individual  variations,  we  must  at  once  be  led 
to  believe  that  individuals  have  been  created  independently — a 
manifest  absurdity. 

But  variations  in  the  same  brood  have  been  found  among  wild 
animals  ;  for  example,  both  the  red  and  gray  varieties  of  the  little 
horned  owl  (Scops  asio)  have  been  taken  from  the  same  nest. 

As  further  examples  of  gradation  between  species  and  variety, 
found  in  nature,  I  only  have  to  select  those  genera  most  numerous 
in  species,  and  best  studied.  Among  birds,  Corvus,  Emp)idonax, 
JButeo,  Falco,  etc.  Eep tiles,  Eutaeiiia,  Anolis,  Lyoodon,  Naja, 
Caudisona^  Elaps,  Oxyhrropus,  etc.  Batrachia,  Rana,  Hyla, 
Clioropliilus^  Borhorocoetes,  AmUy stoma,  Spelerpes,  etc.  Fishes, 
PtycliostomuSf  Plecostomus,  Amiurus,  Sal  mo ,  Pcrca,  and  many 
others. 

In  all  these  groups  of  species,  or  '^genera,"  it  is  impossible  in 
some  cases  to  determine  what  is  variety  and  what  species.  This 
is  notoriously  the  case  with  the  salmon  and  trout  (Sahno),  for  one 
of  the  greatest  opponents  of  close  division  of  species.  Dr.  Giinther, 
of  London,  thought  himself  necessitated,  a  very  few  years  ago,  to 
name  and  describe  half  a  dozen  new  species  of  trout  from  the 
lakes  of  the  British  Islands,  and,  from  being  a  stanch  supporter 
of  the  old  view  of  distinct  creations,  was  completely  converted  to 
evolutionism. 

Such  is  one  of  the  views  which  has  forced  conviction  on  the 
minds  of  thoroughly  honest  men  who  were  not  only  desirous  of 
knowing  the  truth,  but  were  in  many  cases  brought  over  from  a 


EVOLUTION  AND  ITS   CONSEQUENCES.  5 

position  of  strong  opposition.  But  the  earnest  objector  says,  you 
have  not  after  all  shown  me  any  real  transitions  from  species  to 
species  ;  until  that  is  done  your  development  is  but  a  supposition. 

The  all-sufficient  answer  to  this  statement  is  to  be  found  in 
the  imperfection  of  our  system  of  classification.  Thus,  if  we  first 
assume,  with  the  anti-developmentalist,  that  varieties  have  a  com- 
mon parentage,  and  species  distinct  ones,  when  intermediate  forms 
connecting  so-called  species  are  discovered,  we  must  confess  our- 
selves in  error,  and  admit  that  the  forms  supposed  to  have  had 
a  different  origin  really  had  a  common  one.  Such  intermediate 
forms  really  establish  the  connection  between  species,  but  the 
question  is  begged  at  once  by  asserting  unity  of  species,  and, 
therefore,  of  origin,  so  soon  as  the  intermediate  form  is  found  ; 
for,  as  before  observed,  it  is  not  degree,  but  constancy  of  distinc- 
tion, which  establishes  the  species  of  the  zoological  systems. 
Transitions  between  species  are  constantly  discovered  in  existing 
animals ;  when  numerous  in  individuals,  the  more  diverse  forms 
are  regarded  as  *^ aberrant";  when  few,  the  extremes  become 
*^  varieties,"  and  it  is  only  necessary  to  destroy  the  annectant 
forms  altogether  to  leave  two  or  more  species.  As  the  whole  of  a 
variable  species  generally  has  wide  geographical  range,  the  vari- 
eties coinciding  with  sub-areas,  the  submergence,  or  other  change 
in  the  intervening  surface,  would  destroy  connecting  forms,  and 
naturally  produce  the  isolated  species. 

Formerly  naturalists  sometimes  did  this  in  their  studies.  A 
zoologist  known  to  fame  once  pointed  out  to  me  some  trouble- 
some specimens  which  set  his  attempts  at  definition  of  certain 
species  at  defiance.  *' These,"  said  he,  ''are  the  kind  that  I 
throw  out  of  the  window."  Naturalists  having  abandoned  throw- 
ing puzzling  forms  out  of  the  window,  the  result  of  more  honest 
study  is  a  belief  in  evolution  by  nine  tenths  of  them. 

But,  says  the  inquirer  again,  your  variations  and  transitions 
are  but  a  drop  in  the  ocean  of  well-disting-uished  species,  classes, 
etc.  The  permanent  distinction  of  species  is  matter  of  every-day 
observation  ;  your  examples  of  changes  are  few  and  far  between, 
and  utterly  insufficient  for  your  purpose. 

It  is  true  that  the  cases  of  transition,  intermediate  forms,  or 
diversity  in  the  brood,  observed  and  cited  by  naturalists  in  proof  of 
evolution,  are  few  compared  with  the  number  of  well-defined,  iso- 
lated species,  genera,  etc.,  known  ;  though  far  more  numerous 
than  the  book-student  of  natural  history  is  apt  to  discover.     But 


6  GENERAL  EVOLUTION 

although  the  origin  of  most  species  by  descent  has  not  been  ob- 
served, every  one  knows  the  worthlessness  of  argument  based  on  a 
negative.  Unless  these  cases  exhibit  opposing  evidence  of  a  posi- 
tive character,  they  are  absolutely  silent  witnesses. 

He  who  cites  them  against  evolution  commits  the  error  of  the 
native  of  the  Green  Isle  who  testified  at  a  murder  trial.  '^  Al- 
though the  i^rosecuting  attorney  brought  three  witnesses  to  swear 
positively  that  they  saw  the  murder  committed,  I  could  produce 
thirty  who  swore  they  did  not  see  it  done  ! " 

By  the  inductive  process  of  reasoning  we  transfer  the  unknown 
to  the  known,  for  it  is  the  key  of  knowledge.  It  rests  upon  the 
invariability  of  Nature's  operations  under  identical  circumstances, 
and  for  its  application  merely  demands  that  analysis  and  com- 
parison shall  fix  that  the  nature  of  that  of  which  something  is 
unknown  is  identical  with  that  of  which  the  same  thing  is 
known.  We  then  with  certainty  refer  that  which  is  known  as 
an  attribute  of  that  object  of  which  the  same  quality  had  been 
previously  unknown.  The  following  form  exhibits  its  applica- 
tion to  the  question  of  evolution.  As  preliminary  facts  it  may 
be  assumed  that : 

1.  Many  species  are  composed  of  identical  elemental  parts 
which  present  minor  differences. 

2.  Some  of  these  differences  have  been  seen  to  originate  spon- 
taneously from  parents  which  did  not  possess  them,  or,  what  is  the 
same  thing,  are  known  to  exist  in  individuals  whose  parentage  is 
identical  with  others  which  do  not  possess  them. 

3.  The  gradation  of  differences  of  the  same  elemental  parts  is 
one  of  degree  only,  and  not  of  kind. 

4.  Induction. — Therefore  all  such  differences  have  originated 
by  a  modification  in  growth,  or  have  made  their  appearance  with- 
out transmission  in  descent. 

II.     THE   MAN'NER   OE   EYOLUTIOK. 

In  discussing  this  point,  new  evidence  in  favor  of  develop- 
ment must  be  produced,  and  some  statements  of  the  history  of 
the  opinion  made. 

The  laws  which  are  expressed  by  all  that  we  find  of  structure 
in  animals  are  four,  viz.  : 

1.  Homology. — This  means  that  animals  are  composed  of  cor- 
responding parts  ;  that  the  variations  of  an  original  and  fixed 
number  of  elements  constitute   their  only  differences.     A   part 


EVOLUTION  AND  ITS   CONSEQUENCES.  7 

large  in  one  animal  may  be  small  in  another,  or  vice  versa ;  or 
complex  in  one  and  simple  in  another.  The  analysis  of  animals 
with  skeletons  or  vertebrata  has  yielded  several  hundred  original 
elements,  out  of  which  the  28,000  included  species  are  con- 
structed. Different  this  from  the  inorganic  world,  which  can 
only  claim  about  sixty- two  elemental  substances.  The  study  of 
homologies  is  thus  an  extended  one,  and  is  far  from  complete  at 
the  present  day. 

2.  Successional  Relation. — This  expresses  the  fact  that  species 
naturally  arrange  themselves  into  series  in  consequence  of  a  mathe- 
matical order  of  excess  and  deficiency  in  some  feature  or  features. 
Thus  species  with  three  toes  naturally  intervene  between  those 
with  one  and  four  toes.  So  with  the  number  of  chambers  of  the 
heart,  of  segments  of  the  body,  tlie  skeleton,  etc.  There  are 
greater  series  and  lesser  series,  and  mistakes  are  easily  made  by 
taking  the  one  for  the  other. 

3.  Parallelism. — This  states  that  while  all  animals  in  their 
embryonic  and  later  growth  pass  through  a  number  of  stages  and 
conditions,  some  traverse  more  and  others  traverse  fewer  stages ; 
and  that,  as  the  stages  are  nearly  the  same  for  both,  those  which 
accomplish  less  resemble  or  are  parallel  with  the  young  of  those 
which  accomplish  more.  This  is  the  broad  statement,  and  is 
qualified  by  the  details. 

4.  Teleology. — This  is  the  law  of  adaptation  so  much  dwelt  upon 
by  the  old  writers,  and  admired  in  its  exhibitions  by  men  gener- 
ally. It  includes  the  many  cases  of  fitness  of  a  structure  for  its 
special  use,  and  expresses  broadly  the  general  adaptations  of  an 
animal  to  its  home  and  habits. 

Of  course,  these  laws  must  be  all  laws  of  evolution,  if  evolution 
be  true.  And  such  they  are  ;  but  this  is  far  from  being  perceived 
by  some  students,  for  some  of  them  were  in  abeyance  or  neglect 
prior  to  the  stimulus  to  thought  caused  by  the  appearance  of  the 
**  Origin  of  Species." 

Forty  or  fifty  years  ago  Germany  had  been  flooded  with  the 
writings  of  the  ^^physiophilosophs."  Oken  and  Goethe  had  ob- 
tained glimpses  of  the  wonderful  "  unity  in  variety "  expressed 
by  the  laws  of  homology.  The  latter  saw  vertebrae  in  the  seg- 
ments of  the  skull,  and  leaves  in  the  floral  organs  of  plants.  He 
had  found  the  magic  wand,  and  many  were  the  harmonious  visions 
that  delighted  the  laborious  toilers  among  old  bones  and  dusty 
skins  ;  the  patient  haruspices  saw  omens  in  the  intestines  of  birds 


8  GENERAL  EVOLUTION. 

and  snakes,  and  he  whose  hours  were  spent  over  his  lens  ceased 
to  be  a  mere  wonder  monger.  But  fashion  is  fashion,  and  always 
ends  in  absurdity  and  stagnation.  The  physiophilosophs  became 
extravagant,  and  mistook  superficial  appearances  for  realities. 
They  did  not  dream  how  misleading  some  of  the  resemblances 
between  different  elements,  for  example,  of  the  skeleton  may  be, 
and  for  once  German  students  did  not  analyze  exhaustively.  Cu- 
vier  laughed  at  these  seekers  for  beauty,  and  confounded  the  true 
and  the  untrue  in  one  condemnation.  But  the  best  men  labored 
forward  ;  errors  began  to  be  exposed,  and  soon  a  reaction  set  in. 
Another  extreme  followed,  and  the  school  of  Miiller,  at  Berlin, 
denied  the  meaning  of  these  resemblances  and  ceased  to  see  any- 
thing but  differences.  Minute  and  thorough  investigation  flour- 
ished in  their  hands,  and  the  modern  school  of  German  anatomists 
has  seen  no  superiors.  So  the  theory  of  evolution  found  Berlin. 
The  disfavor  in  which  physiophilosophy  was  held  secured  to  evo- 
lution a  cold  welcome,  and  it  has  been  for  Jena  and  other  univer- 
sities to  give  it  its  true  impetus  in  Germany. 

So  it  has  been  with  the  law  of  parallelism.  Some  of  the 
physiophilosophs  declared  it,  stating  that  the  inferior  animals 
were  merely  the  repressed  conditions  of  the  higher.  This  view 
was  taught  by  some  men  in  high  position  in  France.  Their  state- 
ments were,  however,  too  broad  and  uncritical.  The  father  of 
embryology,  von  Baer,  of  Koenigsberg,  declared  there  was  ^'heine 
Rede^^  of  such  theory,  and  Lereboullet  stated  '*  that  it  is  founded 
on  false  and  deceptive  appearances."  Even  Professor  Agassiz  in 
our  day  has  asserted  that  no  embryonic  animal  is  ever  the  same  as 
the  adult  of  another,  though  he  also  once  informed  the  writer  that 
the  embryology  of  two  nearly  related  species  had  never  been  studied 
and  compared.  This  was  subsequently  done  by  Professor  Hyatt, 
of  Salem,  for  the  nautilus  and  ammonite  division  of  mollusks,  and 
at  about  the  same  time  by  the  writer,  for  many  species  of  our  na- 
tive frogs  and  salamanders,  and  the  result  has  been  a  complete 
clearing  up  of  the  confusion  about  parallelism,  and  the  clear  estab- 
lishment of  the  law. 

The  results  attained  are  these  :  The  smaller  the  number  of 
structural  characters  which  separate  the  two  species  when  adult, 
the  more  nearly  will  the  less  complete  of  the  series  be  identical 
with  an  incomplete  stage  of  the  higher  species.  As  we  compare 
species  which  are  more  and  more  different,  the  more  necessarily 
must  we  confine  the  assertion  of  parallelism  to  single  parts  of  the 


EVOLUTION  AND  ITS   CONSEQUENCES.  9 

animals,  and  less  to  the  whole  animal.  When  we  reach  species  as 
far  removed  as  man  and  a  shark,  which  are  separated  by  the  ex- 
tent of  the  series  of  vertebrated  animals,  we  can  only  say  that  the 
infant  man  is  identical  in  its  numerous  origins  of  the  arteries  from 
the  heart,  and  in  the  cartilaginous  skeletal  tissue,  with  the  class  of 
sharks,  and  in  but  few  other  respects.  But  the  imjoortauce  of  this 
consideration  must  be  seen  from  the  fact  that  it  is  07i  single  char- 
acters of  this  hind  that  the  divisions  of  the  zoologist  depend. 
Hence  we  can  say  truly  that  one  order  is  identical  with  an  incom- 
plete stage  of  another  order,  though  the  species  of  the  one  may 
never  at  the  present  time  bear  the  same  relation  in  their  entirety 
to  the  species  of  the  other.  Still  more  frequently  can  we  say  that 
such  a  genus  is  the  same  in  character  as  a  stage  passed  by  the  next 
higher  genus  ;  but  when  we  can  say  this  of  species,  then  their  dis- 
tinction is  almost  gone.  It  will  then  depend  on  the  opinion  of 
the  naturalist  as  to  whether  the  repressed  characters  are  perma- 
nent or  not.  Parallelism  is  then  reduced  to  this  definition  :  that 
each  separate  character  of  every  kind,  which  we  find  in  a  species, 
represents  a  more  or  less  complete  stage  of  the  fullest  growth  of 
which  the  character  appears  to  be  capable.  In  proportion  as  those 
characters  in  one  species  are  contrasted  with  those  of  another  by 
reason  of  their  number,  by  so  much  must  we  confine  our  compari- 
son to  the  characters  alone,  and  the  divisions  they  represent ;  but 
when  the  contrast  is  reduced  by  reason  of  the  fewness  of  differing 
characters,  so  much  the  more  truly  can  we  say  that  the  one  species 
is  really  a  suppressed  or  incomplete  form  of  the  other.  The  denial 
of  this  principle  by  the  authorities  cited  has  been  in  consequence 
of  this  relation  having  been  assigned  to  orders  and  classes,  when 
the  statement  should  have  been  confined  to  single  characters ;  and 
divisions  characterized  by  them.  There  seems,  however,  to  have 
been  a  want  of  exercise  of  the  classifying  quality  or  power  of  *^  ab- 
straction "  of  the  mind  on  the  part  of  the  objectors.  This  faculty 
seems  to  be  by  no  means  so  common  as  one  would  expect,  judging 
from  the  systematic  ideas  of  many. 

To  explain  by  a  few  examples  selected  at  random  :  First,  of 
species  characters,  I  may  cite  the  fact  that  all  deer  are  spotted 
when  young,  and  that  some  of  the  species  of  eastern  and  southern 
Asia  retain  the  spotted  coloration  throughout  life.  All  salaman- 
ders are  uniform,  often  olive  during  a  larval  stage  ;  some  species, 
and  some  individuals  of  other  species,  retain  the  color  in  maturity. 
To  take  a  genus  character  :  all  the  deer  in  the  second  year  develop 


10  GENERAL  EVOLUTION. 

their  first  horn,  which  is  unbranched  and  small,  or  a  "  spike."  A 
genus  of  deer  inhabiting  South  America  never  develops  anything 
else.  To  take  a  character  of  higher  grade  :  the  exogenous  plants 
usually  present  net- veined  leaves,  but  the  first  pair,  or  those  of 
the  plumule,  are  of  much  simpler  structure,  being  often  parallel- 
veined  ;  for  example,  the  cucumbers  and  squashes.  Now,  the  en- 
dogens  usually  produce  nothing  else  than  parallel-veined  leaves,  and 
no  case  is  known  where  a  plant  bearing  this  type  of  leaf  exhibits 
the  net-veined  type  as  its  earliest  growth. 

But  what  do  these  facts  mean  ?  As  in  growth  the  genus  char- 
acters usually  appear  last,  I  will  suppose  a  case  where  one  genus 
represents  truly,  or  is  identical  with,  the  incomj^lete  stage  of  an- 
other one. 

In  A  we  have  four  species  whose  growth  attains  a  given  point, 
a  certain  number  of  stages  having  been  passed  prior  to  its  termi- 

nation,  or  maturity.     In  B  we  have  an- 

A  other  series  of  four  (the  number  a  mat- 
ter of  no  importance),  which,  during  the 
period  of  growth,  can  not  be  distin- 
guished by  any  common,  i.  e.,  generic 
character,  from  the  individuals  of  group 
A,  but  whose  growth  has  only  attained 
to  a  point  short  of  that  reached  by  those 
of  group  A  at  maturity.  Here  we  have  a  parallelism,  but  no  true 
evidence  of  descent.  But  if  we  now  find  a  set  of  individuals  be- 
longing to  one  species  (or,  still  better,  the  individuals  of  a  single 
brood),  and  therefore  held  to  have  had  a  common  origin  or  parent- 
age, which  present  differences  among  themselves  of  the  character 
in  question,  we  have  gained  a  point.  We  know  in  this  case  that 
the  individuals,  a,  have  attained  to  the  completeness  of  character 
presented  by  group  A,  while  others,  Z>,  of  the  same  parentage  have 
only  attained  to  the  structure  of  those  of  group  B.  It  is  perfectly 
obvious  that  the  individuals  of  the  first  part  of  the  family  have 
grown  further,  and,  therefore,  in  one  sense  faster,  than  those  of 
group  b.  If  the  parents  were  like  the  individuals  of  the  more 
completely  grown,  then  the  offspring  which  did  not  attain  that 
completeness  may  be  said  to  have  been  retarded  in  their  devel- 
opment. If,  on  the  other  hand,  the  parents  were  like  those  less 
fully  grown,  then  the  offspring  which  have  added  something 
have  been  accelerated  in  their  development.  I  claim  that  a  con- 
sideration of  the  uniformity  of  nature's  processes,  or  inductive 


EVOLUTION  AND   ITS   CONSEQUENCES.  H 

reasouiug,  requires  me  to  believe  that  the  groups  of  species,  that 
is,  groups  A  and  B,  are  also  derived  from  commou  parents,  and 
the  more  advanced  have  been  accelerated  or  the  less  advanced  re- 
tarded, as  the  case  may  have  been  with  regard  to  the  parents. 

This  is  not  an  imaginary  case,  but  a  true  representation  of 
many  cases  which  have  come  under  notice.  I  can  not  repeat 
them  here,  but  refer  to  the  original  memoirs,  where  they  may  be 
found.  * 

This  is  a  simple  statement  of  the  law  of  '^  acceleration  and  re- 
tardation "  of  some  American  naturalists,  which  probably  expresses 
better  than  any  other  the  ^^  manner  of  evolution,"  the  proposition 
with  which  we  started. 

Hyatt  thus  defines  it  as  seen  in  a  group  of  ammonites  which 
he  studied  :  "  The  young  of  higher  species  are  thus  constantly 
accelerating  their  development,  and  reducing  to  a  more  and  more 
embryonic  condition  the  stages  of  growth  corresponding  to  the 
adult  periods  of  preceding  or  lower  species."  f 

This  form  of  demonstration  of  evolution  is  of  far  wider  appli- 
cation than  that  which  I  first  brought  forward.  X  Iii  the  latter 
case  the  induction  may  be  limited  to  a  certain  range  of  variation, 
but  the  present  law  is  as  extensive  as  the  organic  world  ;  that  is, 
the  ^^positioning"  essential  to  it  is  found  everywhere,  from  the 
lowest  to  the  highest,  and  in  characters  from  the  least  to  the 
greatest  in  import. 

Let  an  application  be  made  to  the  origin  of  tlie  human  species. 
It  is  scarcely  necessary  to  point  out  at  the  start  the  fact,  univer- 
sally admitted  by  anatomists,  that  man  and  monkeys  belong  to 
the  same  order  of  Mammalia,  and  differ  in  those  minor  charac- 
ters, generally  used  to  define  a  '* family"  in  zoology. 

Now,  these  differences  are  as  follows  :  In  man  we  have  the 
large  head  with  prominent  forehead  and  short  jaws  ;  short  canine 
teeth  without  interruption  behind  (above)  ;  short  arms,  and  thumb 

*  See  "  Odgin  of  Genera,  and  Method  of  Creation,"  Naturalists'  Agency,  Salem, 
Massachusetts ;  or  McCalla  &  Stavely,  237  Dock  Street,  Philadelphia. 

f  "  On  the  Parallelism  between  Stages  in  the  Individual  and  those  in  the  Group 
of  the  Tetrabranchiata."     "  Boston  Society  of  Natural  History,"  4to,  1866,  p.  203. 

:j:  It  is  quite  misunderstood  by  Darwin,  as  will  be  sufficiently  evident  from  the 
following  quotation  from  the  last  edition  of  his  "  Origin  of  Species,"  1872,  p.  149: 
"  There  is  another  possible  mode  of  transition,  namely,  through  the  acceleration  or 
retardation  of  the  period  of  reproduction.  This  has  lately  been  insisted  on  by 
Prof.  Cope  and  others  in  the  United  States."  This  has  only  been  dwelt  on  as 
accounting  for  a  very  minor  grade  of  differences  seen  in  race  and  sex. 


12  GENEEAL  EVOLUTIOif. 

of  hind  foot  not  opposable.  In  monkeys  we  have  the  reverse  of 
all  these  characters.  But  what  do  we  see  in  young  monkeys  ?  A 
head  and  brain  as  large  relatively  to  the  body  as  in  man  ;  a  facial 
angle  quite  as  large  as  in  many  men,  with  jaws  not  more  promi- 
nent than  in  some  races  ;  the  arms  not  longer  than  in  the  long-armed 
races  of  men,  that  is,  a  little  beyond  half  way  along  the  femur. 
These  observations  are  made  on  a  half-grown  Cetus  apella,  from 
Brazil,  a  member  of  a  group  more  remote  from  men  than  are  the 
Old  World  apes,  yet  with  an  unusually  large  facial  angle.  At 
this  age  of  the  individual  the  distinctive  characters  are  therefore 
those  of  homo,  with  the  exception  of  the  opposable  thumb  of  the 
hind  foot,  and  the  longer  canine  tooth  ;  nevertheless,  the  canine 
tooth  is  shorter  in  the  young  than  in  the  adult. 

Now,  in  the  light  of  various  cases  observed,  where  members  of 
the  same  sj^ecies  or  brood  are  found  at  adult  age  to  differ  in  the 
number  of  immature  characters  they  possess,  we  may  conclude 
that  man  originated  in  the  following  way  :  that  is,  by  a  delay  or 
retardation  in  growth  of  the  body  and  fore  limbs  as  compared  with 
the  head  ;  retardation  of  the  jaws  as  compared  with  the  brain 
case,  and  retardation  in  the  protrusion  of  the  canine  teeth.  The 
precise  process  as  regards  the  hinder  thumb  remains  obscure,  but 
it  is  probably  a  very  simple  matter.  The  projDortions  of  the 
young  Cehus  apella  enable  it  to  walk  on  the  hind  limbs  with  great 
facility,  and  it  does  so  much  more  frequently  than  an  adult  G. 
capiicinus  with  which  it  is  confined.* 

The  *' retardation"  in  the  growth  of  the  jaws  still  progresses. 
Some  of  our  dentists  have  observed  that  the  last  (3d)  molar  teeth 
(wisdom  teeth)  are  in  natives  of  the  United  States  very  liable  to 
imperfect  growth  or  suppression,  and  to  a  degree  entirely  unknown 
among  savage  or  even  many  civilized  races.  The  same  suppres- 
sion has  been  observed  in  the  outer  pair  of  superior  incisors. 
This  is  not  only  owing  to  a  reduction  in  the  size  of  the  arches  of 
the  jaws,  but  to  successively  prolonged  delay  in  the  appearance  of 
the  teeth.  In  the  same  way  men,  and  the  man-like  apes,  have 
fewer  teeth  than  the  lower  monkeys,  and  these  again  fewer  than 
the  ordinary  Mammalia,  and  this  reduction  has  proceeded  in  rela- 
tion to  an  enlargement  of  the  upper  part  of  the  head  and  of  the 
brain. 

The  cause  of  development  may  be  next  considered,  and  under 

*  The  same  relations  of  man  to  the  anthropoid  apes  have  been  dwelt  upon  by 
Prof.  C.  Yogt. 


EVOLUTION  AND   ITS   CONSEQUENCES.  13 

this  head  may  be  discussed  the  natural  selection  of  Wallace  and 
Darwin  and  other  propositions  of  similar  import. 

'^  Retardation  "  continued  terminates  in  extinction.  Examples 
of  this  result  are  common  ;  among  the  best  known  are  those  of 
the  atrophy  of  the  organs  of  sight  in  animals  inhabiting  caves.  It 
is  asserted  that  the  young  of  both  the  blind  crawfish  {Orcoiiedes 
pellucidus)  and  the  lesser  blind  fish  [TyphlicMliys  suhterraneus) 
of  the  Mammoth  Cave  possess  eyes.  If  these  statements  be  accu- 
rate, we  have  here  an  example  of  what  is  known  to  occur  else- 
where, for  instance,  in  the  whalebone  whales.  In  a  foetal  stage 
these  animals  i30ssess  rudimental  teeth  like  those  of  many  other 
Cetacea  when  adult,  which  are  subsequently  absorbed.  So  also 
with  the  foetal  ox  ;  the  upper  incisor  teeth  appear  in  a  rudimental 
condition,  but  are  very  early  removed.  The  disappearance  of  the 
eyes  is  regarded  by  Dr.  Packard,  with  reason,  as  evidence  of  the 
descent  of  the  blind  forms  from  those  with  visual  organs.  I  would 
suggest  that  the  process  of  reduction  illustrates  the  law  of  *^  re- 
tardation "  accompanied  by  another  phenomenon.  Where  charac- 
ters which  appear  latest  in  embryonic  history  are  lost,  we  have 
simple  retardation,  that  is,  the  animal  in  successive  generations 
fails  to  grow  up  to  the  highest  point  of  completion,  falling  farther 
and  farther  back,  thus  presenting  an  increasingly  slower  growth 
in  the  special  direction  in  question.  Where,  as  in  the  presence  of 
eyes,  we  have  a  character  early  assumed  in  embryonic  life,  retarda- 
tion presents  a  somewliat  different  phase.  Each  successive  genera- 
tion, it  is  true,  fails  to  come  up  to  the  completeness  of  its  prede- 
cessor at  maturity,  and  thus  exhibits  ^^retardation,"  but  this 
process  of  reduction  of  rate  of  growth  is  followed  by  its  termina- 
tion in  the  part  long  before  growth  has  ceased  in  other  organs. 
This  is  an  exaggeration  of  retardation,  and  means  the  early  termi- 
nation of  the  process  of  force-conversion,  which  has  been  previ- 
ously diminishing  steadily  in  activity. 

Thus  the  eyes  of  the  Orconectes  probably  exhibited  for  a  time 
at  maturity  the  incomplete  character  now  found  in  the  young,  a 
retarded  growth  continuing  to  adult  age,  before  the  termination 
of  growth  was  withdrawn  by  degrees  to  earlier  stages.  With  this 
early  termination  of  growth  came  the  phase  of  atrophy,  the  in- 
complete organ  being  removed  and  its  materials  transferred  to 
other  parts  through  the  greater  activity  of  ''  growth-force."  Thus, 
for  the  reduction  of  organs,  we  have  ''retardation  "  ;  but  for  their 
extinction,  ''retardation  and  atrophy." 


14  GENERAL  EYOLUTIOK 

III.    OIT   THE   CAUSES   OF   EYOLUTIOIS'. 

1.  Inductive  Reasoning, 

In  the  present  investigation  we  are  endeavoring  to  discover 
new  principles,  not  to  apply  old  ones.  The  work  is  similar  to 
that  which  occupied  Newton  in  his  investigation  of  the  law  of 
attraction  or  gravitation.  The  process  by  which  we  arrive  at 
general  truths  rests  on  the  consideration  of  a  sufficient  number 
of  observed  facts,  and  the  determined  qualities  which  are  common 
to  all  we  regard  as  a  law.  This  process  requires  for  its  proper 
conduct  a  careful  analysis  and  discrimination  of  the  nature  of  the 
objects  considered  ;  otherwise  fallacy  will  result.  As  exact  analy- 
sis is  not  always  observed  by  the  average  mind,  this  inductive 
reasoning  is  not  always  successfully  employed  by  it,  nor  under- 
stood when  presented  by  others.  In  the  deductive  process  it  is 
more  at  home.  With  an  ascertained  principle  given,  as  some- 
thing like  a  staff  for  the  mind  to  lean  on,  its  application  is  not  so 
difficult ;  but  to  such  a  mind  induction  presents  an  appearance 
of  uncertainty  and  even  of  confusion,  and  these  will  certainly 
exist  until  order  is  evoked  by  the  first  step — classification.  The 
theory  of  evolution  has  thus  been  charged  with  confusion,  as 
though  it  asserted  that  which  overtiirew  the  order  of  nature.  But 
the  confusion  only  exists  in  the  mind  of  such  critics.  The  order 
of  the  creation  is  one  of  the  foundation  facts,  and  thus  enters 
the  inductive  argument  as  one  of  its  elements.  That  conclu- 
sion which  is  consistent  with  this  order  can  not  be  regarded  as  its 
enemy. 

-  2.    On  Natural  Selection. 

In  endeavoring  to  assign  a  cause  for  the  existence  of  the  pecul- 
iar structures  which  define  the  divisions  among  animals,  Messrs. 
Wallace  and  Darwin  have  proposed  the  now  well-known  law  of 
natural  selection.  This  states,  that,  inasmuch  as  slight  variations 
appear  continually  in  all  species,  it  is  evident  that  some  will  be 
more  beneficial  to  the  animal  than  others,  in  its  exertions  to  sup- 
ply itself  with  food,  protect  itself  from  enemies,  the  weather,  etc. 
It  then  asserts  that  those  whose  peculiarities  are  beneficial  will 
excel  those  less  favored,  in  the  successful  use  of  their  jDowers,  and 
hence  will  live  better,  grow  better,  and  increase  more  rapidly. 
That  by  the  force  of  numbers,  if  not  by  direct  conflict,  they  will 
ultimately  supersede  the  weaker  and  destroy  or  drive  them  away. 


EVOLUTION  AND   ITS   CONSEQUENCES.  15 

Then,  as  there  are  many  fields  of  action  and  possibilities  of  ob- 
taining support  in  the  world,  that  the  weaker  will  first  be  driven 
to  adopt  such  of  these  as  their  peculiarities  may  adapt  them  for, 
or  not  exclude  them  from.  Thus  all  the  positions  in  the  world's 
economy  are  filled  and  the  surplus  destroyed.  This  is  styled  by 
Spencer  the  ''^survival  of  the  fittest"  ;  an  expression  both  com- 
prehensive and  exact. 

This  doctrine  is  no  doubt  a  true  one,  and  has  regulated  the 
preservation  of  the  variations  of  species,  and  assigned  them  their 
locations  in  the  economy  of  nature.  It  was  natural  that  this  great 
law  should  have  been  brought  out  by  such  men  as  Darwin  and 
"Wallace,  who  are  by  nature  much  more  of  observers  of  life  in  the 
field,  or  out-door  physiologists,  than  they  are  (or  were)  anatomists 
and  embryologists.  Their  writings  in  their  chosen  field  of  the 
mutual  relations  of  living  beings  in  their  search  and  struggle  for 
means  of  existence  are  admirable,  and  almost  unique,  especially 
some  of  those  of  Darwin. 

It  is  to  be  observed,  however,  that  they  both  (especially  Dar- 
win) start  with  the  variations  observed.  This  is  assumed  at  the 
outset,  and  necessarily  so,  for  ^^ selection"  requires  alternatives, 
and  these  are  the  product  of  variation.  Great  obscurity  has  arisen 
from  the  supposition  that  natural  selection  can  originate  anything, 
and  the  obscurity  has  not  been  lessened  by  the  assertion  often  made 
that  these  variations  are  due  to  inheritance  !  What  is  inheritance 
but  repetition  of  characters  possessed  by  some  (no  matter  what) 
ancestor;  and  if  so,  where  did  that  ancestor  obtain  the  peculiarity? 
The  origin  of  variation  is  thus  only  thrown  upon  an  earlier  period. 

Another  reason  why  natural  selection  fails  to  account  for  the 
structures  of  many  organic  beings  is  the  fact  that  in  expressing 
"  the  survival  of  the  fittest "  it  requires  that  the  structures  pre- 
served should  be  especially  useful  to  their  possessors.  Now,  per- 
haps half  of  all  the  peculiarities  of  the  parts  of  animals  (and 
probably  of  plants)  are  of  no  use  to  their  possessors,  or  not  more 
useful  to  them  than  many  other  existing  structures  would  have 
been.  It  fails  to  account  for  many  characters  which  express  the 
relations  of  homology  and  parallelism,  and  is  almost  confined  in 
its  exhibitions  to  features  which  express  teleology.  This  objection 
has  been  insisted  on  by  Kolliker,  the  writer,  and  by  Mivart ;  and 
now  Huxley,  while  defending  Darwinism  proper  against  the  last- 
named  author,  says  that  *'what  the  hypothesis  of  evolution  wants 
is  a  good  theory  of  variation.^^ 


16  GENERAL  EVOLUTION". 

Plainly  enough,  tlien,  nothing  ever  originated  by  natural  se- 
lection, and  as  the  present  essay  relates  to  the  origin  of  types,  lit- 
tle space  can  be  given  to  its  discussion ;  for  natural  selection, 
important  though  it  be,  is  but  half  the  question,  and  indeed  the 
lesser  half.  It  is  to  the  great  causa,tive  forces  as  are  the  gutters 
and  channels  which  conduct  the  water  in  comi^arison  with  the 
pump  and  the  man  who  pumps  it. 

3.   On  Teleology. 

Two  classes  of  structures  have  been  alluded  to  :  those  which 
are  useful  to  an  animal,  and  those  which  are  not  useful ;  or  the 
adaptive  and  non-adaptive.  Nothing  is  better  known  than  that 
animals  are  well  adapted  to  their  situations  in  the  w^orld,  and  for 
their  needs  as  to  sujDplying  themselves  with  food,  etc.  Some  part 
of  every  species  is  so  constructed  as  to  enable  it  to  live  under  con- 
ditions where  most  other  kinds  of  animals  would  perish.  Thus 
the  sea-rangers,  among  birds,  as  the  great  albatross,  etc.,  possess 
long  and  pointed  wings  ;  while  those  that  live  in  thickets  or 
under  cover  have  short,  round  ones,  as  grouse,  woodcock,  etc. 
Even  our  sparrows — those  that  love  the  bushes  and  swamps,  as 
the  song-sparrow  {Melosjnza  melodia) — have  short,  rounded  wings, 
while  those  that  haunt  trees  have  them  sharper  and  pointed,  as 
the  chipping  and  tree  sparrow  {Spizella  socialis,  pusilla,  etc.). 
Water-frogs  have  their  feet  webbed  ;  land-frogs  have  small  or  no 
webs  ;  while  tree-toads  possess  sucker-like  expansions  of  the  ends 
of  the  toes,  which  secrete  a  glutinous  fluid,  by  which  they  adhere 
to  the  trunks  and  leaves  of  trees.  Finally,  frogs  that  burrow  have 
one  or  more  of  the  bones  of  the  base  of  the  hind  foot  {tarsus) 
modified  into  a  projecting  blade,  like  that  of  a  shovel ;  and,  as  they 
squat  down,  they  literally  sit  into  the  ground,  and  are  soon  out 
of  sight  in  the  hole  which  they  dig  with  these  busy  trowels. 

Cave  insects  have  long  and  delicate  antennae  and  limbs,  ex- 
ceeding those  of  their  out-door  relations  by  much.  Moreover, 
their  usual  lack  of  eyes  is  a  clear  case  of  the  reverse  of  adaptation, 
i.  e.,  the  absence  of  an  organ  where  not  needed. 

Less  attention  has  been  directed  to  the  non-adaptive  charac- 
ters, yet  they  are  as  numerous  as  the  adaptive.  I  do  not  include 
under  this  head  useless  organs  or  parts  only,  but  also  those  which 
are  useful,  but  whose  peculiarities  do  not  relate  to  that  use  as 
advantageous  to  it. 

Notable  examples  of  this  kind  are  to  be  found  in  the  characters 


EVOLUTION"  AND  ITS  CONSEQUENCES.  17 

which  distinguish  all  of  the  higher  groups  of  animals  and  of  plants 
among  themselves.  It  is  easier  to  ask  than  to  answer  what  advan- 
tages the  mammalian  skeleton  possesses  over  the  reptilian  that  it 
should  have  superseded  it.  What  end  was  served  by  aborting 
the  coracoid  bone,  which  in  reptiles  supports  the  shoulder-joint 
from  behind,  answering  to  the  ischium  of  the  pelvis  ?  I  do  not 
know  how  to  answer  this  question  on  a  teleological  basis,  although 
it  involves  one  of  the  principal  characters  of  the  class  of  reptiles. 
What  mechanical  end  was  gained  by  withdrawing  the  rib-bones 
of  two  cranial  segments  into  the  cavity  of  the  ear,  to  become  the 
hammer,  anvil,  and  stirrup  of  the  organ  of  hearing  ?  *  Was  it  to 
perfect  the  auditory  faculty  ?  Scarcely  ;  for  birds  possess  as  re- 
fined and  as  musical  an  ear  as  any  mammals,  and  appear  to  be 
superior  to  them  in  discriminating  power,  yet  in  them  the  ham- 
mer is  the  basal  element  of  the  lower  jaw,  and  the  anvil  supports 
it,  being  entirely  outside  the  cranial  walls.  See  again  one  ground 
of  distinction  between  reptiles  and  batrachians.  The  base  of  the 
brain-case  in  the  former  consists  of  an  axis  of  bony  segments  de- 
veloped in  the  primordial  cartilage,  while  in  the  batrachian  it  is  a 
single  bony  plate,  formed  by  deposit  in  the  membrane  which  origi- 
nally bounded  this  cartilage.  Who  can  assign  any  advantage  of  the 
one  type  above  the  other  which  can  be  looked  upon  as  in  any  way 
related  to  the  external  needs  of  the  animals  of  those  classes  ? 

Another  example  may  be  found  in  the  ankle-joints  of  reptiles, 
birds,  and  mammals.  In  the  first  two  the  hinge  is  between  the 
first  and  second  series  of  tarsal  bones  ;  in  the  mammals,  between 
the  bones  of  the  lower  leg  and  the  first  row  of  tarsal  bones.  Some- 
thing besides  the  superior  mechanical  advantages  of  the  latter  has 
given  it  predominance  over  the  former. 

To  turn  to  the  nautilus  and  ammonite  types  of  Mollusca,  we 
observe  beautiful  illustrations  of  all  the  laws  already  stated.  As 
is  well  known,  these  shells  have  their  tubular  cavity  divided  by 
transverse  partitions.  In  the  nautilus  these  unite  with  the  outer 
wall  by  a  plain  angle,  but  in  various  genera  which  lead  toward  the 
ammonites  this  margin  becomes  complicated.  This  results  from 
an  excessive  growth  of  the  peripheral  part  of  the  partition  or  sep- 
tum, so  that  in  order  to  confine  it  to  the  same  space  of  contact  it 
must  be  folded.  This  plication  takes  place  in  a  symmetrical  man- 
ner.    The  folded  edge  in  Aturia  forms  a  tongue-like  loop  on  each 

*  The  homologies  here  expressed  have  been  rendered  improbable  by  late  investi- 
gation.    The  argument  is,  however,  not  affected. 
2 


18  GENERAL   EVOLUTION". 

side,  on  the  outer  surface.  In  Goniatites  a  fold  is  added  on  the 
back.  In  successive  genera  other  main  folds  are  added,  the  last 
appearing  nearest  the  center  of  the  coil.  These  then  become 
complicated  by  subordinate  undulations  which  in  the  more  com- 
plex forms  become  the  axes  of  a  double  row  of  new  lobes  and  folds, 
the  whole  presenting  symmetrical  lobate  outlines  of  much  com- 
plexity and  beauty. 

But  another  series  of  changes  accompanies  those  of  the  septa, 
and  are  entirely  independent  of  them.  These  relate  to  the  yari- 
ous  degrees  of  winding  of  the  shell.  The  early  form  with  simple 
septa  (Orthoceras)  was  straight,  but  others  which  succeeded  began 
to  turn  their  shell-making  round  an  axis,  thus  commencing  a  par- 
tial coil.  In  some  the  coil  was  very  open  ;  in  others  it  began 
close,  and  then  ceased,  the  shell  finishing  straight.  Others  after 
such  a  course  began  to  wind  again,  while  some  made  a  single  turn 
near  the  middle.  The  most  remote  from -the  starting-point  [A^n- 
monites,  sp.)  made  a  tight  and  complete  flat  coil,  while  some, 
whose  septa  remained  simple,  did  the  same  (JVautilus). 

The  direct  uses  of  these  various  forms  of  septum  and  coil  are 
simply  inexplicable,  and  that  one  of  them  was  any  *^ fitter"  to 
*^ survive"  than  another,  by  virtue  of  its  usefulness,  is  for  me 
more  than  doubtful. 

I  am  tempted  to  continue  this  theme,  for  it  might  be  pro- 
longed indefinitely  by  any  one  familiar  with  the  details  of  ana- 
tomical structure,  but  I  will  only  repeat  that  the  illustrations 
would  be  drawn  chiefly  from  the  characters  of  the  classes,  orders, 
families,  and  other  higher  groups. 

It  is  not  difficult  to  believe,  in  the  case  of  the  useful  structures 
first  cited,  that  the  law  of  natural  selection  has  had  much,  prob- 
ably everything,  to  do  with  the  preservation  of  tbe  animals  pos- 
sessing them  in  the  various  localities  to  which  they  are  adapted. 
But  that  it  has  had  opportunity  to  direct  the  lines  of  progress  in 
the  second  series  is  not  likely.  That  it  had  nothing  to  do  with 
the  origin  of  either,  is  certain. 

4.    On  Groivtli- Force. 

Every  change  by  complication  of  structure  is  by  addition; 
every  simplification  is  by  subtraction.  Every  addition  is  a  matter 
of  growth,  which  is  carried  on  by  a  process  of  nutrition.  The  in- 
quiry respecting  the  origin  of  new  forms  centers  itself  at  once  on 
the  history  of  growth  and  the  influences  affecting  it. 


EVOLUTION  AND   ITS  CONSEQUENCES.  19 

If,  as  I  suppose,  these  additions,  either  adaptive  or  non-adapt- 
ive, be  produced  by  an  acceleration  *  of  growth,  it  is  evident  that 
the  same  immediate  cause  of  that  increase  must  be  potent  in  both 
cases.  That  one  of  the  *^ forces"  is  concerned  in  growth  as  well 
as  in  all  the  active  animal  and  vegetable  processes,  is  obvious  to 
those  who  have  carefully  observed  it.  The  fact  that  growth,  like 
work,  requires  food  for  its  progress  and  continuance,  is  reason 
enough  for  suspecting  the  existence  of  a  force,  and  in  some  cases 
the  relation  between  this  force  and  other  known  forces  may  be 
measured. 

Prof.  Henry  pointed  out  these  facts  many  years  ago,  and 
illustrated  them  by  observations  on  the  growth  of  the  potato  and 
of  the  Qgg.  The  starch  of  the  former,  a  complex  ''organic" 
chemical  compound,  weighs  much  more  than  the  young  shoot 
of  cellulose,  etc.,  into  which  it  is  converted  by  the  process  of 
growth,  so  that  a  portion  of  the  substance  of  the  tuber  has  evi- 
dently escaped  in  some  other  direction.  This  was  found  to  be 
carbonic-acid  gas  and  water,  derived  from  the  slow  combustion  of 
the  starch,  which,  in  thus  ''running  down  "  from  the  complex  or- 
ganic state,  to  the  more  simple  inorganic  compounds,  evolves  an 
amount  of  force  precisely  equal  in  amount  to  the  chemical  force 
(chemism)  requisite  to  bind  together  the  elements  in  the  new  and 
complex  substance  cellulose,  f 

It  is  well  known  that  substances  differ  in  their  capacities  for 
giving  out  different  kinds  of  force.  This,  of  course,  means  their 
capacity  for  converting  one  kind  of  force  into  another.  Thus,  if 
glass  be  rubbed  with  silk,  the  motion  is  converted  into  electricity, 
"while,  if  it  be  rubbed  by  the  hand,  heat  is  the  principal  result. 
In  some  cases  chemical  force,  set  free  by  decomposition,  is  con- 
verted into  light ;  in  others,  heat ;  in  others,  to  electricity,  often- 
er  to  several  at  once.  But  one  substance,  so  far  as  known,  pos- 
sesses the  power  of  converting  this  chemical  force  or  heat  into 
growth-activity,  and  that  is  the  material  out  of  which  the  living 
parts  of  animals  and  plants  are  composed.  This  is  a  protein,  a 
compound  of  carbon,  oxygen,  and  nitrogen  in  the  order  of  rela- 
tive quantity,  with  a  smaller  proportion  of  hydrogen,  the  whole 
being   often   associated  with  still   smaller  quantities  of   sulphur 


*  For  the  definition  of  this  term  see  first  article,  in  May  number  of  '*  Penn 
Monthly."      (Antea,  p.  11.) 

f  "Agricultural  Report  of  Patent  Office,"  185*7. 


20  GENEKAL  EYOLUTIOK 

and  phosplionis.      In  its  mechanical  aspect,  as  the  material  out 
of  which  structures  and  tissues  are  made,  it  is  called  protoplasm. 

This  substance  exhibits  two  different  phenomena  of  force- 
energy,  viz.,  motion  and  growth.  Motion  is  exhibited  by  con- 
traction and  expansion,  but  which  is  the  active  state  and  which 
the  passive  state  is  matter  of  question.  Some  physiologists  regard 
*^  contractility "  as  the  energetic  state.  Kadcliffe  believes  that 
extension  is  the  energetic  condition,  and  contraction  a  rebound 
or  discharge  of  the  extending  force.  He  finds  dead  protoplasm 
to  be  a  dielectric,  and  believes  that  in  life  each  muscular  fibrilla 
acts  like  a  Ley  den  jar.  It  has  been  demonstrated  that  the  outer 
layer  of  the  sheath  of  a  muscular  fibrilla  is  positively  electrified  in 
life,  while  the  cut  extremities  are  negative,  and  it  is  shown  by 
Eadcliffe  that  the  inner  side  of  the  sheath  becomes  negatively 
electrified  by  induction.  The  attraction  of  the  opposite  electrici- 
ties on  opposite  sides  of  the  sheath  compresses  and  elongates  it, 
thus,  according  to  his  theory,  producing  muscular  extension.  The 
nervous  cells  and  tubes  he  believes  to  act  in  the  same  way ;  the 
difference  being  that  the  walls  and  sheaths  are  in  a  state  which 
prevents  compression  and  extension.  The  phenomena  of  mus- 
cular extension  and  nervous  tension  he  believes  to  be  terminated 
by  a  discharge  of  the  force,  such  as  takes  place  in  electrical  fishes, 
but  in  much  smaller  quantity.  Thus  motive  force  resides  as  a 
form  of  electricity  in  protoplasm,  and  in  highly  organized  animals 
is  specialized  into  neurism. 

As  to  growth-force,  all  its  exhibitions  may  be  reduced  to  cell- 
division,  cell-nutrition,  and  cell-origin.  Cell-division  exhibits 
two  prominent  varieties.  In  both  the  cell  nucleus  first  divides  ; 
in  the  ordinary  mode,  the  cell-wall  contracts  at  opposite  points, 
forming  approaching  plications,  which,  when  they  meet,  divide 
the  cell.  In  the  other  mode  or  proliferation,  the  divisions  of  the 
nuclei  approach  the  cell-walls,  which  bulge  opposite  to  them, 
forming  diverticula,  which  isolate  themselves  by  opposing  con- 
tractions at  the  base,  which  meet  as  before.  The  nature  of  the 
force  thus  displayed  is  as  yet  only  speculative,  and  its  demonstra- 
tion will  result  largely  from  observation  on  cell-origin  from  homo- 
geneous protoplasm.  Eadcliffe  suggests  an  ingenious  theory. 
He  supposes  that  the  protoplasm  acquires  an  external  layer  differ- 
entiated from  the  internal  mass  by  exposure  to  and  contact  with 
external  substances,  and  that  the  electricity  generated  in  the  in- 
terior is  distributed  on  the  under  surface  of  this  stratum.     That 


EVOLUTIOI:^  AND  ITS  CONSEQUENCES.  21 

this  induces  opposite  electricity  on  the  external  surface,  which,  as 
in  the  muscular  cell,  causes  compression,  and  therefore  extension 
of  the  stratum.  This  extends  itself  beyond  its  contents,  which 
may  be  attenuated,  filling  the  space,  or  contracting,  forms  the 
nucleus. 

This  view  will  not,  however,  account  for  nucleus  and  cell- 
division,  which  are  the  subsequent  and  principal  exhibitions  of 
growth-force.  Perhaps  the  following  suggestions  may  throw  some 
light  on  it.  Should  a  polar  tendency  appear  in  the  nucleus,  were 
the  protoplasm  of  the  proper  viscidity,  the  poles  being  of  like 
electric  name,  would  tend  to  separate  by  repulsion,  thus  forming 
the  hour-glass  shape  so  well  known,  and  afterward  division. 
This  nucleus  division  would  inevitably  be  followed  by  division 
of  the  cell-wall,  if  its  inner  face  were  electrified  in  opposition  to 
the  nucleus.  For  the  wall  being  attracted  toward  it  equally  all 
round,  the  separation  of  the  two  nuclei  would  be  followed  by  an 
incurvature  of  the  walls  opposite  the  interval  between  the  nuclei, 
in  order  that  each  should  maintain  a  position  equidistant  from 
its  center.  Further  divergence  would  result  in  the  completion 
of  the  cell-wall  of  each,  apart  from  the  other.  This  process 
would  be  supported  by  nutrition  of  the  cell,  which  proceeds  by 
the  passage  through  the  cell-wall  to  the  nucleus,  of  additional 
protoplasm  from  the  blood.  Of  course,  the  prime  question  is  as 
to  whether  polarity  can  appear  in  the  nucleus.  That  growth 
is  first  polar  appears  probable  on  consideration  of  the  globular 
and  discoidal  forms  of  the  lower  animals,  and  that  this  principle 
lies  at  the  basis  of  the  growth  of  the  higher  is  rendered  equally 
probable  by  the  phenomena  of  symmetry  of  different  kinds,  as 
bilateral,  anteroposterior,  etc.  The  electricity  supplied  to  the 
outer  sheaths  of  muscular  fibrillae  is,  according  to  Dubois  Eey- 
mond,  positive.  That  covering  the  surface  of  the  nucleus  must 
be  thought  to  be  positive  also,  if  it  be  effected  in  opposition  to  the 
inner  wall  of  the  cell-wall,  which  is  known  to  be  negative  by  ex- 
periment. But  in  that  case  it  would  be  difficult  to  perceive  why 
it  should  not  fill  the  cell  by  attraction  to  the  wall.  If,  on  the 
other  hand,  it  be  a  generator  of  negative  electricity,  it  would  re- 
tain its  integrity  and  induce  a  temporary  change  in  the  wall. 
The  transmission  of  protoplasm  through  the  cell-wall  to  the 
nucleus  would  produce  an  accumulation  of  electricity  to  be  dis- 
charged in  extension,  or  a  disturbance  of  equilibrium,  to  be  fol- 
lowed by  polarity  and  division  ;  but  the  conditions  under  which 


22  GENERAL  EVOLUTION". 

these  results  would  appear  are,  of  course,  unknown.  The  me- 
chanical arrangement  and  condition  of  the  parts  would  have 
much  to  do  with  it. 

We  are,  however,  here  in  the  arcana  of  life,  and  the  forms  of 
law  which  rise  before  the  mental  vision  are  but  as  the  statues  of 
Memnon  that  greet  the  toiler  on  the  river  of  mysteries  ;  they  loom 
upon  its  banks  in  twilight,  and  the  w^hen,  the  how,  and  the  where- 
fore remain  unanswered.  But  the  river  of  Africa  is  yielding  her 
secrets,  and,  though  the  life  that  she  nourishes  may  be  the  last  she 
will  give  up,  it  is  no  less  surely  promised  to  the  patient  inquirer. 

A  great  advance  toward  an  explanation  of  the  operation  of  this 
growth-force  was  made  in  the  demonstration  of  the  fact  that  its 
highest  exhibitions  are  confined  to  the  multiplication  of  cells  by 
division  of  pre-existent  ones,  by  contraction  of  their  nuclei  and 
walls  in  lines  which  finally  meet. 

The  construction  of  additional  parts  consists  solely  of  this  cell- 
growth,  but  the  character  of  the  result  is,  of  course,  dependent  on 
the  position  at  which  this  addition  takes  place.  It  may  be  at  the 
terminus  of  a  limb  to  add  another  toe,  or  on  the  wall  of  an  artery 
to  add  a  valve.  It  may  be  in  the  brain  to  add  a  band  of  fibers, 
or  on  the  edge  of  a  muscle  to  extend  its  width. 

That  tissues  are  made  of  cells  of  original  or  altered  shape,  sepa- 
rate or  confluent  (flown  together)  is  well  known.  That  the  ar- 
rangement of  tissues  into  organs  is  due  to  the  direction  of  this 
multiplication  is  also  true.  Thus  a  gland  is  a  collection  of  folli- 
cles, each  of  which  is  a  bagging  of  a  plane  tissue.  This  bagging- 
is  an  exaggerated  convexity,  which  is  occasioned  mechanically  by 
excess  of  cell-growth  at  one  spot  on  a  uniform  surface.  Solid 
parts  are  all  formed,  in  the  first  insta7ice,  of  simple  segments. 
These  are  parts  produced  in  a  straight  rod  by  excessive  elongation 
or  growth  ;  the  process  being  as  before,  the  division  of  cells  and 
distribution  of  homogeneous  protein  between  them.  All  this  is 
derived  from  the  study  of  homologies  combined  with  embryology, 
and  the  result  is  wonderful,  and  simplifies  at  once  our  ideas  of  the 
action  of  the  growth-force.  It  is  mainly  a  repetition  of  cell-divis- 
ion, the  result  as  to  structure  being  entirely  dependent  on  the 
influences  which  locate  its  activity  and  regulate  its  amount. 

Now,  its  amount  will  depend  on  the  capacity  of  the  existing 
organism  to  convert  heat,  etc.,  into  it ;  and  the  form,  as  to  tissue, 
etc.,  in  which  it  appears,  depends  no  doubt  on  the  complexity  of 
the  machines  or  organs  of  which  the  organism  is  composed.     In 


EVOLUTION  AND   ITS   CONSEQUENCES.  23 

the  case  of  the  higher  organisms  we  have  muscle,  converting  the 
results  of  nutrition  into  muscle  ;  skin  and  nails  making  more  skin, 
etc. ;  brain  making  more  brain  ;  bone  making  more  bone. 

The  prime  question  is  the  cause  of  the  location  of  growth- 
force.  Experiments  on  this  point  are  greatly  needed,  and  in  their 
absence  it  will  be  necessary  to  take  a  wide  survey  of  facts. 

A  given  animal  Organism  can  only  convert  a  given  amount  of 
force,  and  that  capacity  must  remain  uniform  so  long  as  the 
machine  or  structure  remains  the  same.  If,  however,  an  addition 
to  its  work  is  developed  in  one  quarter,  a  subtraction  from  some 
other  region  must  take  place  if  the  whole  amount  remain  the  same. 
When,  then,  a  useful  organ  is  added,  subtraction  from  some  less 
important  locality  must  result,  and,  as  a  consequence,  the  latter 
must  become  still  less  prominent  in  the  general  economy.  Hence, 
the  development  of  the  useful  class  of  organs  already  cited  must 
always  be  accompanied  by  a  corresponding  disappearance  of  use- 
less ones.  This  would  be  by  reduction  or  retardation.  But,  in 
the  case  of  the  complex  folds  of  the  margins  of  the  septa  in  the 
ammonite,  useless  parts  are  added  by  acceleration.  Here  a  gradual 
increase  in  the  amount  of  growth-force  must  be  believed  in. 

The  representation  of  simple  growth-force,  i.  e.,  the  result  of 
bathmism,  not  specially  located,  is  seen  in  general  addition  to  size. 
In  domestication  careful  feeding,  associated  with  protection  against 
all  exhausting  exposure  or  exertion,  tends  to  this  increase  of  size. 
This  is  well  known  to  be  the  case  in  hogs  and  cattle  and  animals 
of  quiet  and  easy  life.  The  reverse  conditions,  as  poor  food,  ex- 
posure, and  disproportionate  exertion,  reduce  the  size  ;  witness  the 
Maryland  breed  of  cattle,  and  the  semi-wild  hogs  of  the  Southern 
States.  This  matter  is,  however,  nicely  balanced  with  the  pro- 
duction of  motion,  for  if  the  latter  be  excessive,  or  the  supply  of 
material  for  consumption  be  insufiBcient,  growth-force  must  be 
evolved  in  less  amount. 

It  will  be  necessary  here  to  state  that  the  supply  for  the  con- 
version of  all  the  forces  of  the  body  is  derived  from  the  nutriment 
as  circulated  in  the  blood. 

But  the  condition  of  plethora  of  growth-force  is  also  the  one 
highly  favorable  for  the  appearance  of  variations  of  structure,  or 
the  location  of  growth-force  in  new  places.  Domesticated  animals 
are  notorious  for  this  variation,  while  the  still  more  numerous  ex- 
amples of  *^ protean"  species  in  nature  are  always  predominant 
forms,  abundant  in  individuals  and  widely  spread.     For  example. 


24  GENERAL  EVOLUTION. 

the  wolf,  the  red  fox,  the  red-tailed  hawk,  the  garter-snake,  the 
tiger,  salamander,  etc. 

That  the  yariability  depends  on  a  peculiar  condition  of  the  ani- 
mals themselves,  and  not  on  domestication,  excepting  in  so  far  as 
it  produces  these  conditions,  is  plain,  not  only  from  the  above 
facts,  but  from  those  observed  in  domestication.  It  is  well  known 
that  while  pigeons,  fowls,  cattle,  dogs,  etc.,  are  variable,  or  '^  pro- 
tean," the  peafowl  (Pavo)  has  maintained  its  specific  characters 
with  great  accuracy  during  a  period  of  domestication  as  long  as 
that  of  the  other  species  named.  The  same  may  be  said  of  the 
guinea  {Numida)  and  the  turkey  {Meleagris).  These  facts  show 
that  domestication  is  only  a  remote  cause  of  variability. 

5.    On  the  Location  of  Growth-Force. 

With  the  fact  of  increase  of  general  growth-force  before  us, 
have  we  any  others  which  can  guide  us  in  fixing  on  a  cause  for  its 
special  location  ?  It  is  plain  that  the  useful  additions  which  have 
constituted  certain  genera,  families,  orders,  etc.,  what  they  are, 
must  have  been  produced  as  a  consequence  of  the  existence  of  a 
need  for  them  ;  or,  on  the  other  hand,  being  created  first,  they 
must  have  sought  for  use,  and  found  it.  But  what  are  the  rela- 
tive chances  of  truth  for  these  two  propositions  ?  In  the  second 
case,  admitting  evolution  as  proved  (see  Part  I),  we  perceive  that 
an  almost  infinite  chance  exists  against  any  usual  amount  of 
variation,  as  observed,  producing  a  structure  which  shall  be  fit  to 
survive  in  consequence  of  its  superior  adaptation  to  external  cir- 
cumstances. It  would  be  incredible  that  a  blind  or  undirected 
variation  should  not  fail  in  avast  majority  of  instances  to  produce 
a  single  case  of  the  beautiful  adaptation  to  means  and  ends  which 
we  see  so  abundantly  around  us.  The  amount  of  attemjot,  failure, 
and  consequent  destruction,  would  be  preposterously  large,  and 
in  no  wise  consistent  with  the  facts  of  teleology  as  we  behold 
them. 

What  of  the  opposite  view  ?  We  have  in  its  support  the  well- 
known  facts  of  determination  of  nutritive  fluid  during  use  of 
parts,  not  only  for  supplying  fuel  for  the  motions  of  use,  but  also 
for  growth-force  and  material  for  the  increase  in  bulk  of  the  part 
used.  Who  has  not  remarked  the  large  size  of  the  hands  of  the 
laborer,  and  of  the  nails  of  the  working-woman  ?  Who  can  not 
remember  some  of  the  countless  examj)les  of  certain  modifications 
of  form  being  associated  with  special  excellence  of  use  of  the  parts 


EVOLUTION"  AND  ITS   CONSEQUENCES.  25 

in  different  races  of  the  same  species  of  individuals  of  common 
parentage,  showing  that  they  must  have  grown  with  the  history 
of  those  races  ?  Who  does  not  know  the  short,  wide  jaws  of  the 
bull-dog,  with  their  oblique  teeth,  produced  by  the  expansion  of 
the  zygomata  to  accommodate  the  huge  temporal  muscles  so  neces- 
sary for  maintaining  a  firm  hold  of  its  enemy.  Then  the  long  and 
full  nose  of  the  hound,  and  its  more  extended  turbinate  bones — 
how  closely  is  this  connected  with  its  developed  scent ;  while  the 
light  muscular  forms  of  the  greyhound  are  undoubtedly  necessary 
to  its  well-known  speed.  If  it  be  said  that  these  variations  have 
not  resulted  in  a  single  change  of  structure  worthy  of  note  by  a 
systematist,  we  can  point  to  the  Japanese  dog,  where  the  excessive 
reduction  of  the  jaws  anteriorly  has  resulted  in  a  total  loss  of  some 
of  the  premolars  and  molars.  The  loss  of  molar  and  incisor  teeth 
from  shortening  of  the  jaws,  in  the  human  species,  has  been  al- 
ready noted.  The  number  of  such  instances  is  very  great,  but,  as 
space  to  enumerate  them  fails,  it  is  only  necessary  to  add  that  they 
are  characters  of  high  importance  in  a  systematic  sense.  Their 
importance  will  be  more  readily  conceded  in  remembering  the 
proposition,  already  stated,  that  species  are  simply  isolated  varie- 
ties, and  of  similar  origin. 

Confirmatory  of  this  view  are  the  facts  already  cited  with  ref- 
erence to  the  relation  of  motive  to  growth-force.  The  force  in- 
volved in  both  being  seen  to  be  similar,  perhaps  identical,  the 
former  represents  its  energetic  state  as  discharge  and  motion,  the 
other  energetic  without  discharge,  in  the  growth  of  cells.  And 
whatever  determines  this  force  to  a  given  part  of  the  body  must 
then  probably  result  in  both  of  its  exhibitions,  dependent  on  the 
kind  of  cells  which  receive  it.  As  above  remarked,  the  conditions 
which  determine  the  result  are  unknown,  except  that  the  two 
kinds  of  muscular  cells  are  the  only  ones  in  which  elongation  is 
strongly  marked. 

Another  reason  for  believing  in  use  as  a  cause  of  structural 
change  is  the  manner  in  which  the  same  useful  structures  have 
evidently  appeared  on  totally  distinct  stems,  as  an  evident  adapta- 
tion to  the  same  circumstances  in  which  the  different  types  have 
been  equally  placed.  Thus  the  birds  of  prey  possess  the  hooked, 
often  toothed,  beak,  appropriate  for  tearing  and  destroying  ani- 
mals. Their  stock  is  the  same  as  that  of  the  cuckoos  and  parrots, 
and  even  of  the  pigeons.  The  butcher-birds  are  of  the  division  of 
songsters,  not  widely  removed  from  the  thrushes,  and  far  enough 


26  GENERAL  EVOLUTION. 

from  the  raptores,  yet  tlie  same  hook  and  dentate  bill  reappears  in 
them,  as  adapted  to  flesh-eating  habits. 

Among  the  reptiles,  which  were  no  doubt  originally  land  ani- 
mals, and  derived  from  batrachians,  we  haye  a  large  number 
adapted  to  swimming  in  the  ocean,  and  these  not  all  of  the  same 
stock.  Thus  the  Plesiosauri  are  crocodilian  in  relationship,  while 
the  Pythonomorpha  of  America  were  of  the  same  that  produced 
the  snake  and  lizard.  Again,  the  same  modification  appears  in  the 
Cetaceans,  or  whale,  etc.,  among  mammals  which  are  primarily  a 
terrestrial  division. 

It  is  a  nice  point  of  phylogeny  (or  the  science  of  genealogy)  to 
ascertain  whether  adaptive  or  strictly  ^'bathmic"  (or  embryonic 
grade)  characters  came  first  in  a  time  in  a  given  group.  Among 
frogs  we  have  four  divisions.  One  has  an  embryonic  mouth  and 
embryonic  breast-bones  ;  another,  embryonic  mouth  and  complete 
breast-bones  ;  the  third,  embryonic  breast  -  bone  but  complete 
mouth;  and  the  fourth,  with  both  complete.  The  first  is  the  lowest 
and  probably  the  oldest  in  time ;  agreeably  to  this  supposition,  it 
is  distributed  over  the  whole  earth.  The  second  is  East  Indian 
and  African ;  the  third  and  most  extensive  is  Australian  and 
American  ;  while  the  fourth  is  confined  to  the  Old  World  and 
JSTorth  America.  The  second,  third,  and  fourth  divisions  possess 
corresponding  series  of  genera  of  different  structure  adapted  to 
different  modes  of  life.  Some  have  shovels  for  burrowing,  some 
webs  for  swimming,  and  some  palettes  for  adhering  to  branches 
and  leaves  of  trees.  If  these  characters  were  first  fixed,  then  those 
with  the  more  perfect  breast-bone  and  mouth  are  descendants  of 
those  with  the  less  perfect ;  if,  on  the  other  hand,  the  conditions 
of  mouth  and  breast-bone  were  first  fixed,  then  each  division  thus 
defined  in  its  special  region  was  modified  into  the  subdivisions, 
each  adapted  to  a  special  mode  of  life.  I  have  called  these  parallel 
divisions  "homologous  groups,"  and  probably  the  origin  of  the 
embryonic  modifications  has  sometimes  come  first,  and  sometimes 
the  adaptive  structures  have  preceded.  Nevertheless,  the  lowest  or 
most  embryonic  division  will  often  have  developed  its  own  adapt- 
ive divisions,  and  each  of  these  will  agree  in  'producing  descend- 
ants which  have  advanced  in  the  embryonic  scale,  and  so  produce 
homologous  groups. 

For  these  and  other  reasons  it  is  concluded  that  the  useful 
characters,  defining  natural  divisions  of  animals,  have  been  pro- 
duced by  the  special  "location  of  growth-force"  by  use.     Useless 


EVOLUTION   AND   ITS   CONSEQUENCES.  27 

ones  have  been  produced  by  location  of  growth-force  without  the 
influence  of  use,  or  by  its  subtraction,  due  to  a  disturbance  of 
equilibrium,  consequent  on  the  special  location  elsewhere. 

But  we  go  back  to  the  origin  of  the  question  in  investigating 
the  action  of  growth-force  undisturbed  by  the  interference  of  lo- 
cating influences.  This  is  only  to  be  ascertained  by  an  examina- 
tion of  lower  organisms  in  connection  with  the  higher.  A  point 
that  first  strikes  the  student  of  higher  animals  is,  that  after  he  has 
proved  the  law  of  Jiotnology  to  be  true,  as  regards  different  animals 
when  compared,  he  further  finds  that  the  parts  of  the  same  ani- 
mal are  also  homologous,  that  is,  right  hand  and  left,  front  and 
behind,  bottom  and  top  are  also  constructed  on  the  same  plan,  so 
as  to  be  reduced  to  the  same  elemental  parts.  This  is  described 
under  the  names  of  "anteroposterior"  and  ^* bilateral  symmetry," 
etc.*  These  laws  apply  to  all  parts  of  the  organism,  and,  though 
there  appear  to  be  exceptions,  these  are  traceable  to  a  common 
symmetrical  type,  the  change  wrought  being  one  form  of  speciali- 
zation. It  is  not  surprising  then  that  the  lower  we  descend  in  the 
scale  of  life  the  less  marked  is  the  departure  from  the  entirely 
symmetrical  disposition  of  parts  as  regards  the  common  center. 
This  is  beautifully  seen  in  the  EacUata,  etc.,  where  the  jelly-fish, 
the  star-fish,  and  the  sea-urchin  are  familiar  examples. 

But  these  are  complex  compared  with  forms  below  them.  The 
minute  Polycystina  construct  shells  of  beautiful  sculpture  or 
tracery  ;  but,  though  they  present  many  forms,  they  may  be  all 
referred  as  modifications,  to  the  symmetrically-marked  disk.  Of 
cellular  animals,  Trichodiscus  represents  a  discoidal  aggregate, 
and  Actinophrys  a  globular  mass  of  cells.  Monas  and  its  allies 
consist  of  one  or  several  cells  in  globular  form. 

Lastly,  in  the  first  appearance  of  life  in  the  most  complex  ani- 
mal we  have  first  a  cell,  which,  then  '^  segmenting,"  divides  itself 
so  as  to  become  a  globular  mass  of  identical  cells,  arranged  about 
the  center. 

From  the  cellular  animal  upward  the  operation  of  addition  of 
parts  is  then  one  of  repetition,  and  that  centrifugally  in  the  case 
of  bodies  which  are  developed  in  all  planes,  or  peripherally  in  those 
which  are  in  one  plane. 

Thus  the  complication  of  the  edges  of  the  septa  of  the  am- 
monites is  accounted  for.    First,  the  growing  animal  was  supplied 


See  Prof.  B.  Wilder,  in  Proceed.  Boston  Society  Nat.  Hist. 


28  GENERAL  EVOLUTION. 

with  an  excess  of  growth-force.  The  type  of  the  preceding  gen- 
eration being  strictly  adhered  to  according  to  the  laws  of  inherit- 
ance, the  only  opportunity  for  its  exhibition  was  necessarily  after 
the  inherited  parts  were  completed  by  acceleration.  The  results 
could  only,  therefore,  be  exhibited  on  the  edges  of  the  new  septa 
and  free  margin  of  the  outer  wall.  As  the  older  growths  me- 
chanically restrained  the  new  septa  from  mere  extension,  folding 
or  plication  must  have  resulted  from  the  crowding  of  additional 
surface  into  the  small  space.  This  folding  would  take  the  form 
of  simple  branching,  and  then  "repetition"  of  the  process  by  a 
refolding  of  the  outlines  of  the  first  fold.  The  edge  would  thus 
have  the  digitate  or  pinnately  branched  appearance  it  is  known  to 
present. 

Another  case  of  folding  is  that  of  the  brains  of  the  higher 
mammals,  including  man.  This  was  occasioned  by  excess  of 
growth-force  distributed  to  the  circumference  (from  an  inherited 
central  region),  exceeding  in  amount  that  of  the  space  (skull)  in 
which  it  was  inclosed.  Folding  was  necessary  for  its  accommoda- 
tion in  the  contracted  space.  This  is  a  highly  useful  modification. 
Another  case  like  that  of  the  ammonite  above  cited,  whose  use  is 
not  so  readily  determined,  but  which  illustrates  excess  of  growth- 
force  on  some  other  account,  is  that  of  cotyledonary  leaves  in  some 
plants.  In  these  cases  the  growth  of  the  leaf  is  accelerated,  re- 
quiring plication  for  its  accommodation. 

We  therefore  have  the  two  laws  regulating  the  "  location  of 
growth-force  "  irrespective  of  use,  viz. :  1,  the  centripetal  or  po- 
lar tendency ;  2,  the  peripheral  tendency ;  both  more  or  less  de- 
termined by  the  inherited  central  or  first  grown  parts. 

There  is,  however,  another  element  which  in  animals  disturbs 
the  symmetrical  direction  of  growth-force  besides  use,  and  which 
precedes  use,  i.  e.,  effort.  Use  presupposes  a  part  to  use,  and  a 
simple  part  is  sufficient  for  its  influence,  so  that  it  be  usable  ;  but 
the  first  beginnings  of  few  structures  are  usable.  As  Mivart  has 
objected  to  natural  selection,  that  the  first  rudiments  of  organs 
could  never  be  sufficiently  important  to  an  animal  to  give  it  a 
preference  in  the  struggle  for  existence,  so  it  might  be  urged 
against  the  theory  of  use  that  rudiments  are  generally  useless, 
and  could  not  have  been  originated  by  use. 

The  effect  of  use  is,  howcA-er,  twofold.  The  contact  with  ob- 
jects used  has  some  effect  in  stimulating  nutrition,  as  well  as  the 
exertion  of  the  muscles  necessary  to  use.     But  determination  of 


EVOLUTION   AND   ITS   CONSEQUENCES.  29 

nutritive  fluid  is  well  known  to  be  under  the  influence  of  nerve- 
force.  How  imagination  stimulates  secretion  is  seen  in  the  famil- 
iar example  of  the  flow  of  saliva  in  anticipation  of  food ;  a  very 
different  example  is  the  phenomenon  of  blushing  under  emotional 
stimulus.  Nevertheless,  it  is  not  evident  that  growth  can  result 
with  any  such  facility  in  a  fully  grown  animal.  It  is  thought  that 
the  effort  becomes  incorporated  into  the  metaphysical  acquisitions 
of  the  parent,  and  is  inherited  with  other  metaphysical  qualities 
by  the  young,  which  during  the  period  of  growth  is  much  more 
susceptible  to  modifying  influences  and  is  likely  to  exhibit  struct- 
ural change  in  consequence.  Certain  it  is  that  acceleration  ceases 
with  growth,  and,  as  the  young  of  animals  are  not  in  complete  re- 
lation with  the  surrounding  world,  the  influences  controlling  it 
must  be  inherited.  This  consideration  renders  it  doubly  probable 
that  the  results  of  effort  on  the  part  of  the  j)arent  appear  in  change 
of  structure  in  the  offspring. 

Of  course,  immense  numbers  of  cases  of  continued  effort  can  be 
produced  by  the  objector,  in  which  no  structural  modification  has 
resulted.  There  are  various  reasons  why  a  modification  should 
not  take  place.  In  the  first  place,  the  exertion  of  use  must  be 
great,  habitual,  and  long-continued  ;  in  the  next  place,  abundant 
food  must  be  at  hand  ;  finally,  growth-force  must  be  to  spare  in 
the  growing  young,  either  from  some  less  necessary  part  or  by  ex- 
cess. Now,  cases  are  probably  not  rare  where  none  can  be  spared 
from  another  part  without  injuring  the  efficiency  or  viability  of 
the  animal ;  hence,  all  such  changed  individuals  would  perish 
through  some  form  of  natural  selection  or  disease. 

Domesticated  animals  can  be  pointed  out  where  effort  and  use 
have  long  been  put  forth  in  the  service  of  man  without  changing 
structure.  But  such  effort  is  not  to  be  compared  for  a  moment 
with  that  put  forth  by  animals  in  a  wild  state,  in  seeking  food  or 
protection  from  enemies.  The  protection  furnished  by  man,  and 
consequent  release  from  the  struggle  for  existence,  has  reduced 
the  chances  for  such  variations  greatly.  Nevertheless,  variations 
profitable  to  man  have  resulted  ;  witness  the  race-horse  and  carter. 

In  cases  where  one  side  of  the  body  is  used  in  excess  of  the 
other,  unsymmetrical  development  would  be  counteracted  by  the 
law  of  polar  or  centrifugal  growth,  all  that  might  be  acquired  by 
the  one  side  being  inherited  by  both.  Even  this  original  sym- 
metry has,  however,  been  overcome  in  some  types,  as  in  the 
flounders  (in  the  jaws  and  teeth  as  used  parts).     This  part  of 


30  GENERAL  EVOLUTION. 

the  subject  is  purely  hypothetical,  however  probable,  but  the  as- 
pect of  the  discussion  will  be  materially  brightened  to  the  reader, 
if  he  have  previously  adopted,  with  the  author,  the  principle  that 
evolution  has  been  the  mode  of  origin  of  the  present  life-forms  of 
the  earth. 

Reverting  now  to  those  beings  which  are  either  in  part  or  en- 
tirely destitute  of  the  power  of  determining  these  movements,  as 
plants,  various  causes  present  themselves  as  modifiers  of  the  polar 
or  centripetal  activity  of  growth-force.  In  the  case  of  a  plant,  the 
medium  in  which  it  grows  modifies  the  result ;  for  example,  the 
downward  growing  axis  or  root  differs  much  from  the  upward 
aerial  portion  or  stem.  Aquatic  plants,  supported  beneath  or  on 
the  surface  of  the  water,  lack  the  strong  stems  and  braces  neces- 
sary to  air-growing  plants  ;  while  of  the  latter,  those  with  weak 
stems  develop  tendrils  and  other  supports.  In  these  cases  physical 
laws  have  been  the  guides  of  growth-force.  In  the  case  of  bright 
colors,  which  we  know  to  be  impossible  in  vegetation  without  sun- 
light, the  influence  is  chemical. 

The  first  physical  law  is,  that  growth-force,  uninfluenced  by 
inherited  peculiarity,*  or  any  stronger  influence  locating  a  nutri- 
tive fluid,  must  develop  extent  in  the  direction  of  least  resistance, 
and  density  on  the  side  of  greatest  resistance,  when  not  too  great. 
The  illustration  of  this  statement  would  be  that  a  globular  mass  of 
cells  brought  to  the  point  of  Junction  of  two  media,  as  water  and 
earth  or  air  and  earth,  elongates  in  the  direction  of  the  medium  pre- 
senting the  least  resistance,  i.  e.,  air.  Thus  a  longitudinal  develop- 
ment would  originate  from  a  centrifugal,  and  a  repetition  of  the 
same  process  would  produce  branches.  The  reason  why  repetition 
should  appear  along  the  sides  instead  of  as  continued  prolongation 
of  the  axis,  arises  probably  from  the  difficulty  of  conveying  fluid 
nutritive  material  far  from  the  base  as  a  source  of  supply,  and  the 
occurrence  of  various  mechanical  obstacles  easy  to  be  conceived. 
In  low  plants,  where  nutrition  is  absorbed  by  all  parts  of  the  axis, 
which  branch,  as  the  subterranean  parts  of  fungi  {myceliwn),  dif- 
ference of  local  supply  would  produce  an  effect.  In  higher  plants, 
where  fluid  nutriment  is  only  introduced  at  one  point  (the  root), 
and  conveyed  by  special  layers  of  cells  or  tubes,  the  difficulty  of 
maintaining  supply  at  a  distance  from  its  source  would  encourage 
lateral  repetition  or  branching,  f 

*  This  is  supposed  to  be  due  to  atomic  peculiarity  of  cell-substance. 

f  The  great  power  exerted  in  a  given  direction  by  growth-force  due  to  gradual 


EVOLUTION  AND   ITS   CONSEQUENCES.  31 

6.    On  the  Origin  of  Intelligence, 

Leaving  this  part  of  the  subject,  we  approach  one  of  higher 
interest,  viz.,  the  effects  of  the  metaphysical  or  mental  acquire- 
ments of  animals  on  their  exertions  in  effort  and  use.  The  growth 
of  the  mind  in  animals  has,  no  doubt,  followed  the  same  laws 
obeyed  by  that  of  man  ;  the  difference  being  that  the  lower  forms 
have  remained  permanently  fixed  in  stages  early  passed  by  the 
lord  of  living  beings.  The  foundation  qualities  from  which  all 
the  phenomena  of  intellect  may  be  derived  are,  the  powers  of  re- 
tentiveness  (memory)  and  of  perceptions  of  resemblance  and  dif- 
ference. These  traits  are  well  known  to  be  possessed  by  many 
animals,  and  perhaps  in  some  degree  by  all.  Their  possession 
will  be  modified  by  the  power  of  exercising  attention,  which,  in 
its  turn,  will  depend  on  the  sensitiveness  of  the  animal  to  impres- 
sions^n  other  words,  the  ease  with  which  consciousness  may  be 
aroused. 

The  origin  of  the  disposition  to  take  food  will  be  the  rudiment 
of  all  that  appears  as  ivill  in  higher  animals,  and  which,  though 
supposed  to  guide,  is  the  creature  of  so  many  stimuli.  This  ori- 
gin is  supposed  by  metaphysicians  to  be  the  result  of  education 
of  the  '*  spontaneous  activity"  of  animals  by  their  pleasures  and 
pains. 

The  brain  of  man  and  of  other  animals  is  an  organ  which  re- 
ceives and  retains  pictures  and  impressions,  both  painful  and 
pleasurable.  The  retention  of  these  pictures  is  not  a  state  of  con- 
sciousness, but  they  may  be  brought  into  the  consciousness  accord- 
ing to  the  law  of  "contiguity,"  or  association.  That  is,  that  the 
recurrence  in  the  actual  of  some  object  or  event,  which  was  per- 
ceived on  a  former  occasion,  at  or  near  the  same  time  as  another 
object  or  event  not  again  repeated  in  the  actual,  will  bring  the 
latter  before  the  consciousness.  So,  also,  the  revival  of  one  such 
picture  will  bring  within  the  mental  vision  others  impressed  on 
the  mind  at  or  near  the  same  time  as  the  first.  These  events  may 
have  been  in  the  reality  either  painful  or  pleasurable.  On  the 
recurrence  of  circumstances  which  on  a  former  occasion  resulted 
in  pain,  the  resuscitation  of  the  mental  picture,  then  impressed  on 

acquisition  and  inheritance  is  illustrated  by  the  plantain,  Plantago  majoy.  Although 
without  axis,  it  has  been  observed  by  James  C.  Cresson,  in  the  Philadelphia  Park, 
and  Alfred  Cope,  on  his  drive,  to  force  itself  through  a  solid  bed  of  hard  vulcanite 
pavement,  several  inches  in  thickness. 


32  GENERAL  EVOLUTION". 

the  memory,  produces  an  anticipation  of  the  pain,  and  the  ani- 
mal at  once  flies  from  the  source  of  danger.  So,  also,  with  pleasur- 
able objects,  the  resultant  action  being  the  reverse,  or  an  attraction 
to  the  object.  In  both  cases  a  previous  experience  of  the  relation 
between  the  object  and  the  sensation  of  pleasure  or  pain  must  have 
been  had. 

There  is^  in  addition,  the  power  of  determining  differences  and 
likenesses,  by  which  contiguities  or  associations  are  originated  in 
the  mind,  of  a  character  different  from  that  resulting  from  the 
relations  of  times  of  receipt  of  the  impression.  Such  contiguities 
recall  pictures  to  the  consciousness  in  consequence  of  their  resem- 
blances in  essential  qualities. 

On  these  two  bases,  together  with  the  perceptive  faculties,  rest 
the  complex  phenomena  of  the  animal  and  human  minds.  They 
are  probably  physiological  functions  of  brain  tissue,  for  the  follow- 
ing reasons,  among  others  : 

1.  Impressions  are  conveyed  by  physical  means  to  the  brain. 
The  brain  can  only  receive  a  given  number  at  a  time  without  ex- 
haustion, and  is  prepared  to  receive  more  after  being  nourished. 
Impressions  long  forgotten  are  revived  in  certain  states  of  disease. 
Impressibility  and  memory  are  most  marked  during  growth,  and 
diminish  with  age. 

2.  If  impressions  are  physically  produced  and  preserved  in  the 
brain,  those  made  at  or  near  the  same  time  would  remain  close 
together  in  the  brain,  and  this  material  proximity  would  be  the 
^*  contiguity "  according  to  which  they  would  come  before  the 
consciousness. 

3.  Classification  or  appreciation  of  resemblances  takes  place 
unconsciously  in  the  mind  (by  ''  unconscious  cerebration  ").  Re- 
semblances not  seen  at  the  time  of  impression  suddenly  flash  into 
the  consciousness  on  a  subsequent  revival  of  it.  The  "  contigu- 
ity "  to  like  things  thus  established  may  be  more  or  less  lasting  in 
the  mind  than  the  contiguity  of  circumstances  under  which  the 
impression  was  made. 

4.  As  ^^ contiguity"  in  time  is  believed  to  be  revived  by 
contiguity  in  location  of  impressions  in  the  ^^i^erceptive"  part 
of  the  brain,  so  *^  contiguity  "  of  resemblance  may  be  believed  to 
depend  on  contiguity  of  location  in  the  "reflective"  part  of  the 
brain. 

The  retention  of  the  contiguities  of  time  and  of  resemblance 
constitute  the  basis  of  education  of  an  animal,  and  its  intelligence 


EVOLUTION  AND  ITS   CONSEQUENCES.  33 

will  be  in  proportion  to  the  number  and  comj)lexitjof  these  ac- 
quisitions. 

The  lowest  exhibitions  of  contiguity,  or  association  in  time, 
do  not  require  a  nervous  system  for  their  display.  The  Protozoa, 
which  are  without  nervous  system,  exhibit  its  results  in  their  de- 
terminate seizure  of  some  small  objects  as  food  and  rejection  of 
others.  The  sea  anemones  (Actinia)  display  some  preferences  as 
to  the  substances  to  which  they  attach  themselves.  All  power  of 
taking  food  implies  the  retention  of  the  impression  of  pleasure  on 
first  accidentally  coming  in  contact  with  it.  This  power  is  then 
present  in  protoplasmic  beings  of  the  simplest  type. 

All  the  movements  of  animals  have  been  shown  to  depend  on 
a  direction  of  this  motive  force,  consequent  on  a  necessity  for 
avoiding  pain  and  obtaining  pleasure.  It  may  be  regarded,  more- 
over, as  a  truth  that  heightened  vitality  or  energetic  conversion 
of  force  is  always  a  state  of  pleasure,  while  depressed  vitality  is 
generally  the  cause  (as  well  as  a  consequence)  of  pain.  Hence  the 
pleasurable  nature  of  taking  food,  and  the  early  education  of  an 
animal  in  the  distinction  between  objects  nutritive  and  non-nutri- 
tive. 

It  is  well  known,  however,  that  food  may  be  taken,  and  many 
or  all  other  functions  and  acts  be  performed  automatically,  or  in 
a  state  of  unconsciousness.  This  is  as  much  the  case  with  the 
highest  powers  of  thought  (as  in  unconscious  cerebration)  as  with 
the  humblest  acts  which  satisfy  bodily  wants.  The  question  then 
arises  whether  these  acts  may  not  arise  in  a  state  of  unconscious- 
ness. So  far  as  our  own  self-knowledge  goes,  we  would  reply  in 
the  negative.  All  intellectual  functions  are  produced  by  educa- 
tion, and  education  involves  consciousness  at  every  step.  Other 
habitual  and  automatic  acts  were  originated  consciously,  but  the 
contiguity  of  parts  of  the  act  becoming  impressed  on  the  brain, 
future  repetitions  of  it  are  reflex  or  unconscious.  We  have  seen 
that  the  development  of  the  habits  of  animals  is  in  strict  obedi- 
ence to  the  preference  for  pleasure  and  avoidance  of  pain.  Pleas- 
ures and  pains  of  course  express  sensations  which  involve  con- 
sciousness. It  then  appears  to  me  that,  in  the  lowest  animal,  con- 
sciousness must  be  present  at  the  time  of  origin  of  every  habit, 
but  that  it  may  have  been  soon  lost  in  each  case,  and  the  habit 
become  automatic. 

If  this  position  be  true,  every  subsequent  addition  to  or  change 
of  habits  must  have  been  accompanied  by  a  resuscitation  of  con- 

3 


34:  GENERAL  EVOLUTION. 

sciousness.  But  how  is  consciousness  aroused  in  the  cases  which 
we  can  investigate — that  is,  in  our  own  sjoecies  ?  In  the  common 
case  of  sleep,  a  mere  sound  is  sufficient  to  cause  its  return.  In 
syncope  and  other  forms  of  loss  of  consciousness,  a  sudden  shock, 
as  of  cold  water  thrown  on  the  face,  will  often  restore  it.  In 
ordinary  states,  comjiulsion  or  pressure  will  produce  a  more  in- 
tense degree  of  consciousness.  Indeed,  in  many  j)ersons  conscious- 
ness varies  greatly  under  different  influences ;  thus  a  dreamy  state 
naturally  follows  a  lack  of  nutrition  of  the  brain,  as  during  a  fast, 
but  the  mind  is  readily  aroused  from  it  by  a  strong  or  sudden  im- 
pression made  on  the  senses  or  by  an  effort  of  will.  It  is,  hence, 
to  be  believed  that  in  animals  whose  acts  may  be  largely  automatic 
consciousness  is  aroused  by  exceptional  sights,  sounds,  hunger, 
and  other  sensible  impressions,  the  more  readily  in  proportion  to 
the  development  of  the  sensory  ganglia  of  the  brain.  In  the  low- 
est animals,  consciousness  will  be  aroused  with  much  greater  diffi- 
culty, and  life  must  be  in  part  a  blank,  and  in  part  a  dream,  at 
rare  intervals  illumined  by  gleams  of  consciousness  produced  un- 
der the  influence  of  strong  external  stimulus.  At  these  times  of 
awakening  we  must  believe  that  new  movements  are  instituted, 
which  will  become  habitual  in  proportion  to  the  extent  to  which 
they  are  repeated. 

From  what  is  known  of  reflex  actions,  it  is  evident  that  move- 
ments may  become  habitual,  and  hence  automatic,  wherever  cellu- 
lar or  gray  nerve-substance  exists.  Thus,  movements  instigated  by 
the  spinal  nerves  derive  their  automatism  from  the  spinal  medul- 
la. This  axis  no  doubt  derived  the  original  nerve-force  from  the 
brain,  but  repetition  of  the  act  under  the  original  stimulus  con- 
fers the  automatic  power  on  the  spinal  cord  or  ganglionic  center 
as  certainly  as  on  the  brain.  This  must  of  necessity  follow  the 
complication  of  nervous  structures  by  addition  to  the  original 
center.  Thus  are  explained  the  automatic  movements  of  the 
frog's  or  centipede's  legs  in  the  well-known  experiments,  when 
separated  from  the  brain  or  principal  nervous  center. 

Greater  difficulties  are  experienced  in  accounting  for  the  origin 
of  the  automatic  movements  of  plants.  It  is  evident,  however, 
that  many  of  these,  perhaps  all,  are  not  due  to  the  energy  of  mo- 
tive-force, but  are  phenomena  of  growth-force  alone.  Motion  is 
produced  by  the  change  of  direction  imparted  to  growth-force  by 
the  influence  of  heat,  light,  contact,  etc.  This  will  largely  follow 
as  a  consequence  of  the  longer  persistence  of  growth  in  plants 


EVOLUTION  AND  ITS  CONSEQUENCES.  35 

than  in  animals.  In  some  of  the  yery  lowest  plants  movement 
wonl'd  seem  to  be  similar  to  that  seen  in  the  lowest  animals.  The 
origin  of  intelligence  is  then  to  be  found  in  the  first  traces  of  con- 
sciousness. But  inquiry  will  go  further  in  the  search  for  truth. 
One  school  of  physiologists  believes  consciousness  to  be  due  to  cer- 
tain molecular  changes  of  nerve  (i.  e.,  brain)  substance.  No  doubt 
these  are  essential  to  consciousness  ;  yet  it  is,  at  least,  utterly 
inconceivable  that  any  molecular  condition  should  be  capable  of 
recognizing  either  pleasure  or  pain.  Here  we  find  the  first  ap- 
pearance of  the  '^feelings,"  that  part  of  the  human  mind  which 
deserves  to  be  called,  par  excellence,  '*the  soul,"  and  which  is 
the  ^Mocator"  of  all  the  forces  which  go  to  build  up  the  tis- 
sues, organs,  and  parts  of  the  body ;  and  hence  the  organic  type 
of  the  intellect  and  even  of  the  will.  For  if  we  find  growth-force 
to  be  a  correlative  of  physical  force,  and  subject  to  motive-force 
for  its  *Mocation,"  so,  while  we  find  that  motive-force  is  in  like 
manner  but  another  equivalent  of  ordinary  force,  we  find  it  also 
subordinate  to  this  principle  which  "locates"  it. 

7.    On  Intelligent  Selection. 

We  will  now  retrace  our  steps  along  the  line  of  causes  and 
effects,  and  see,  if  possible,  the  nature  and  results  of  "intelligent 
selection." 

Protoplasm,  homogeneous  or  cellular,  discharges  a  force  called 
"motive-force,"  or  neurism,  which  it  converts  from  surrounding 
forces  by  virtue  of  its  molecular  (chemical)  or  atomic  constitu- 
tion. Its  spontaneous  exhibitions  as  movements  bring  it  into 
contact  with  surrounding  objects,  when,  if  sufficiently  sensitive 
to  impressions,  consciousness  of  a  pleasurable  or  painful  charac- 
ter is  aroused.  Then  in  proportion  to  its  sensitiveness,  and  the 
strength  of  the  impression,  the  protoplasm  retains  the  latter  in 
an  unconscious  way,  and,  on  the  subsequent  recurrence  of  the  ob- 
ject to  the  consciousness,  the  pleasurable  or  painful  attribute  is 
also  revived  by  the  law  of  "contiguity."  The  "vital  principle" 
interfering  restrains  the  motive-force  from  exercise  toward  it,  if 
it  be  painful,  or  releases  it  for  motion  toward  it,  if  it  be  pleasur- 
able. This  quality  of  the  vital  principle  is  a  power  of  choice,  and, 
in  so  far  as  consciously  exercised,  is  will*  Nothing  is  better 
known  than  that  acts  originated  consciously  may,  by  repetition, 

*  For  further  development  of  this  subject  see  Part  IV  of  this  book. 


36  GENERAL  EVOLUTION. 

come  to  be  exercised  unconsciously,  or  as  habits.  The  form  these 
habits  take,  will  depend  on  the  opportunities  and  conditions 
offered,  for  instance,  in  the  matter  of  food,  by  the  surrounding 
order  of  things.  Motive-force  is,  of  course,  only  another  name 
for  effort  and  use  ;  the  former  being  a  putting  forth  by  means  of 
conducting  material  or  organs,  without  executive  apparatus ;  the 
latter  always  requiring  organs  or  parts  by  which  to  execute. 

If,  as  previously  assumed,  effort  and  use  locate  growth-force, 
cellular  structure  will  appear  in  the  directions  indicated  by  the 
activity  of  motive-force.  It  is  converted  by  protoplasm  from  heat 
and  chemism,  or  one  only  of  these.  That  it  does  not  require  dif- 
ferentiated *^ motive-force"  as  a  source,  is  proved  by  the  growth 
of  plants,  which  have  no  motion  proper. 

Growth-force,  by  its  ^^  repetitive "  action,*  creates  organs. 
These  at  first  will  be  extremely  simple,  but,  as  machines,  at  once 
increase  the  power  of  the  animal  to  produce  motive-force  by  con- 
version, whether  the  machine  be  a  digestive  apparatus  for  the  ap- 
propriation of  the  material,  or  a  mechanical  one  for  the  exercise 
of  the  force,  the  former  necessarily  preceding  the  latter  in  time. 

With  the  increased  power  of  assimilation  (digestion)  comes  a 
larger  amount  of  material  for  increased  exhibition  of  growth-force, 
a  part  being  burned  or  otherwise  converted  into  the  force,  and  a 
part  remaining  as  the  material  from  which  the  cells  are  construct- 
ed. In  the  latter  23art  of  the  growth-period  a  considerable  portion 
is  usually  consumed  for  motive-force. 

In  the  history  of  the  material  environment,  various  changes  of 
condition  succeeded  each  other.  Changes  of  level  took  place  ; 
waters  were  purified  by  precipitation  of  chemical  compounds ; 
fresh  waters  were  established  ;  the  atmosphere  deprived  of  various 
gases  ;  new  mineral,  and  especially  vegetable,  products  took  their 
appropriate  places.  All  these  offer  a  vast  variety  of  food-supply 
and  opportunity  for  the  pleasurable  discharge  of  motive-force,  and, 
under  the  laws  pointed  out,  efforts  of  animals  were  directed  in  va- 
rious lines,  as  the  conditions  presented  themselves.  Thus  execu- 
tive organs  were  produced  of  varied  character.  Some  acquired 
limbs  and  others  wings  for  transportation  from  place  to  place. 
What  a  vast  addition  to  their  impressions  must  have  been  acquired 
by  the  first  animals  which  could  thus  leave  the  place  of  their 
birth  !    How  many  new  "contiguities"  were  established,  and  how 


*  « 


See  "  Method  of  Creation,"  on  the  Law  of  Repetition. 


EVOLUTION  AND  ITS  CONSEQUENCES.  37 

many  new  habits  originated  !  Look  again  at  the  acquisition  of 
teeth.  From  a  soft  uniform  diet  the  animal  no  doubt  gradually 
learned  to  appropriate  hard  substances,  and  what  a  world  of  ex- 
perience and  consequent  habit  must  have  been  at  once  placed  in 
its  way  ! 

These  acquisitions  are  of  course  mental,  and  include  both 
kinds  of  contiguity,  viz.,  that  of  succession  in  time,  and  that  of 
association  through  resemblance.  Animals  choose  between  objects 
chiefly  in  accordance  with  the  first  mode,  but  are  not  lacking  in 
the  second  quality.  As  an  example  of  the  latter,  classification  ac- 
cording to  color  is  exhibited  by  some  birds,  which  choose  brightly 
colored  objects  and  reject  dull  ones — the  Australian  bower-bird, 
for  instance. 

As  is  well  known  to  metaphysicians,  these  acquisitions  lead  to 
'^predication"  and  "forethought."  Thus  a  hound  becomes  ac- 
quainted with  the  habit  of  a  buck  or  rabbit  in  doubling,  or  in  fol- 
lowing a  given  circuit.  The  recurrence  of  the  chase  recalls  the 
habit  in  consequence  of  contiguity  of  the  impression  of  the  former 
pursuit  of  the  animal  and  the  course  it  took.  The  hound  then 
supposes  or  "  predicates  "  that  the  deer  will  repeat  the  course.  We 
know  that  some  do  so  from  the  fact  that  they  have  been  observed 
to  cut  off  the  curves  in  the  animal's  track,  or  to  station  themselves 
at  the  point  where  the  deer,  for  instance,  will  pass.  In  the  sec- 
ond act  forethought  is  also  involved.  The  hound  sacrifices  the 
lesser  pleasure  of  the  chase  for  the  greater  one  of  securing  the 
prey.  In  forethought,  experience  having  taught  which  circum- 
stance results  in  greater  and  which  in  less  pleasure,  action  is  re- 
strained in  the  presence  of  the  second  for  the  sake  of  procuring 
the  first.  Thus  in  ants,  immediate  pleasure  suggests  a  life  of  labor 
enough  for  present  wants,  and  ease  for  the  remaining  time ;  but 
the  greater  pleasure  of  existence  during  some  time  of  scarcity  has 
induced  some  of  them  to  lay  up  a  store,  which  has  develoj^ed  into 
the  complete  protection  against  winter  they  display  in  cold  cli- 
mates. 

In  the  cases  cited  it  is  perfectly  evident  that  the  hound  would 
never  have  learned  to  predicate  had  he  not  had  limbs  to  bring  him 
in  contact  (by  pursuit)  with  the  habits  of  the  buck.  Nor  would 
the  ant  have  learned  to  provide  if  it  had  not  been  furnished  with 
the  jaws  necessary  to  the  excavation  of  chambers  and  the  carrying 
of  food.  And  neither  would  have  performed  these  mental  acts 
had  they  not  possessed  nervous  centers  capable  of  sensation,  reten- 


38  GENEKAL  EVOLUTIOi^. 

tion,  and  classification.  But  the  development  of  these  qualities 
depended  on  the  possession  of  the  executive  organs. 

Thus  intelligence  of  various  degrees  has  resulted — first,  from 
possession  of  executive  organs ;  secondly,  establishment  of  con- 
tiguities by  their  use ;  tliirdly,  from  classifications  based  on  con- 
tiguities. 

There  are  two  notable  examples  of  the  great  advance  in  mental 
accomj)lishment  inaugurated  by  the  acquisition  of  an  executive 
organ.  The  first  is  the  acquisition  of  the  hand  by  the  monkey. 
Any  one  who  has  compared  their  manners  with  those  of  the  si3e- 
cies  of  unguiculate  (clawed)  animals — as,  for  example,  the  dog — 
must  be  struck  by  the  immense  advantage  possessed  by  the  for- 
mer. To  begin  with,  it  renders  the  monkey  an  expert  climber 
and  catcher  of  moving  objects.  Then  he  greatly  increases  his 
habits  of  observation  by  the  facility  with  which  he  brings  objects 
before  his  eyes.  The  minuteness  of  his  criticism  is  aided  by  his 
power  of  manipulating  with  his  fingers.  He  learns  the  results  of 
tlirowing.  A  cautious  monkey,  set  on  a  strange  animal  or  per- 
son, does  not  rush  at  them  to  bite  like  the  dog,  but  takes  the  more 
refined  method  of  throwing  sticks  and  stones.  In  obtaining  ob- 
jects, if  they  be  out  of  reach,  a  monkey  uses  a  stick  to  draw  them 
in  with.  In  a  Cetus  capucinus,  in  my  possession,  a  leather  strap 
was  preferred,  and  was  thrown  with  great  dexterity,  and  the  ob- 
ject always  secured  by  drawing  it  nearer  in  loops  of  the  strap.  If 
the  strap  were  sometimes  thrown  out  of  reach,  the  monkey  would 
use  a  stick  or  poker  in  order  to  obtain  it  again.  All  this  would 
have  been  quite  imj^ossible  without  a  hand.  This  facility  has  not 
been  lost  on  the  intelligence  of  the  monkeys.  Their  curiosity  is 
proverbial,  and  no  animal  can  compare  with  them  as  successful 
thieves  ;  moving  m  bands,  with  watchers  stationed,  and  taking 
pains  to  store  their  booty  in  their  cheek-pouches  while  they  have 
opportunity,  and  not  wasting  time  in  eating  exclusively. 

Another  instance  is  that  of  man.  Here  the  acquisition  con- 
sisted of  vocal  organs  capable  of  speech.  Any  means  of  com- 
municating and  recording  thoughts  had  the  stupendous  conse- 
quence of  rendering  the  acquisitions  of  one  man  or  class  of  men 
the  common  property  of  all.  Another  consequence,  equally  im- 
portant, is  the  preservation  of  successive  races  of  men  from  the 
necessity  of  passing  through  the  experiences  of  those  that  pre- 
ceded them,  and  the  enabling  them  to  commence  their  intellectual 
life  nearly  where  the  others  left  off.     So  great  would  necessarily 


EVOLUTION  AND  ITS   CONSEQUENCES.  39 

De  the  location  of  activity  in  the  brain,  that  its  stages  of  growth 
would  be  the  principal  changes  of  structure  to  be  witnessed  in 
human  history,  together  with  those  which  should  result  from  loss 
of  growth-force  in  other  regions  by  abstraction. 

To  return  to  the  material  aspect  of  the  case.  The  discrimina- 
tion between  pleasure  and  pain  locates  motive-force,  which  is 
derived  from  without.  Motion  or  use  locates  growth-force,  also 
derived  from  without,  and  thus  produces  organs  out  of  material 
derived  from  without.  These  organs  diversify  the  directions  of 
motion.  From  new  movements  arise  new  pleasures  and  pains, 
and  motion  is  again  '* located"  in  its  exhibitions  in  some  particu- 
lar directions,  and  restrained  in  others.  These  directions  depend 
on  external  circumstances  at  the  first.  The  determination  of 
motion  to  certain  lines  locates  growth-force  in  those  lines,  and 
new  parts  are  produced,  which  are  further  executive  organs  and 
types  of  structure.  We  now  repeat  the  circuit.  New  executive 
organs  introduce  new  contiguities,  the  number  depending  on  the 
general  complication  of  the  animal  in  connection  with  that  of  the 
organ,  and  new  pleasures  and  pains  result.  The  pleasures  again 
determine  activity,  and,  under  the  circumstances  already  men- 
tioned, growth-force  is  again  located. 

In  these  facts  lies  the  explanation  of  the  principle  of  direction 
or  location  of  executive  structures  about  the  head,  termed  by 
Prof.  Dana  ^^cephalization."  The  increasing  demands  of  in- 
telligence locate  growth-force  round  its  organ,  the  brain,  etc., 
while  such  location  reacts  by  furnishing  means  of  increased  ac- 
tivity of  mind. 

These  conjunctions  of  growth  with  executive  capacity,  consti- 
tute a  class  of  *^ expression  points";  points  attained  without 
leaps,  and  abandoned  without  abruptness,  but  constituting  great 
steps  of  progress,  pregnant  with  future  results. 

The  part  played  by  ^Mntelligent  selection"  remains  to  be 
considered.  I  have  heretofore  spoken  only  of  variation  of  types, 
and  not  dwelt  on  their  persistence.  This  is  a  most  important 
consideration,  for  most  men  see  a  great  deal  more  of  the  latter 
than  the  former.  Species  present  their  characters  intact  for  long 
periods,  and  many  structural  peculiarities  have  had  great  range 
in  time. 

I  recur  to  the  origin  of  the  "location  of  growth-force,"  i.  e., 
the  direction  of  motive-force.  This  is  located  by  the  appreciation 
of  pleasure  and  pain.     Now,  every  one  knows  that  different  ani- 


40  GENERAL  EVOLUTION. 

mals  of  the  same  species  yary  exceedingly  in  their  sensitiveness 
to  exterior  influences  ;  that  is,  they  differ  in  the  degree  in  which 
the  same  object  affects  their  consciousness.  That  which  excites 
one  is  unnoticed  by  another ;  what  fills  one  with  alarm  scarcely 
rouses  the  attention  of  another.  It  is  well  known  also  that  differ- 
ences in  the  power  of  retention  are  to  be  found  in  the  same  spe- 
cies of  animals.  The  variations  in  persistence  of  memory  are 
very  great.  While,  therefore,  one  individual  of  a  species  will  ac- 
quire a  store  of  '^  contiguities,"  another  of  the  same  will  possess 
but  few.  In  other  words,  the  degree  with  which  objects  are 
impressed  on  the  consciousness,  and  the  degree  with  which  they 
are  returned  to  the  consciousness,  vary  greatly  in  the  same  spe- 
cies. Here  we  have  the  basis  for  the  origin  of  totally  different 
unconscious  habits  and  reflex  actions,  and  consequent  divergences 
in  the  "location  of  growth-force." 

Those  in  which  these  impressibilities  are  most  highly  devel- 
oped will  accumulate  mental  acquisitions  most  rapidly ;  in  other 
words,  they  will  be  the  most  intelligent  of  their  species.  While 
others  follow  the  old  routine  of  once  acquired  and  then  inherited 
habits,  those  in  whom  consciousness  most  frequently  recognizes 
events  will  originate  new  acts  and  new  habits. 

Intelligence  is  a  conservative  princijole,  and  always  will  direct 
effort  and  use  into  lines  which  will  be  beneficial  to  its  possessor. 
Here  we  have  the  source  of  the  fittest — i.  e.,  addition  of  parts  by 
increase  and  location  of  growth-force,  directed  by  the  influence  of 
various  kinds  of  compulsion  in  the  lower,  and  intelligent  option 
among  higher  animals. 

Thus,  intelligent  choice,  taking  advantage  of  the  successive 
evolution  of  physical  conditions,  may  be  regarded  as  the  originator 
of  the  fittest,  while  natural  selection  is  the  tribunal  to  which  all 
the  results  of  accelerated  growth  are  submitted.  This  preserves 
or  destroys  them,  and  determines  the  new  points  of  departure  on 
which  accelerated  growth  shall  build. 

If  the  above  positions  be  true,  we  have  here  also  the  theory  of 
the  develoi3ment  of  intelligence  and  of  other  metaphysical  traits. 
In  accordance  with  it,  each  trait  appropriates  from  the  material 
world  the  means  of  perpetuating  its  exhibitions  by  constructing  its 
instruments.  These  react  by  furnishing  increased  means  of  exer- 
cise of  these  qualities,  which  have  thus  grown  to  their  full  expres- 
sion in  man. 


11. 

ON  THE   OEIGm  OF   GENERA. 

Introduction. — The  present  fragmentary  essay  is  a  portion  of 
what  other  occupation  has  prevented  the  author  from  completing. 
It  does  not,  therefore,  amount  to  a  complete  demonstration  of  the 
points  in  question,  but  it  is  hoped  that  it  may  aid  some  in  a  classi- 
fication of  facts  with  a  reference  to  their  signification.  When  all 
the  vast  array  of  facts  in  possession  of  the  many  more  learned 
than  the  writer  are  so  arranged,  a  demonstration  of  the  origin  of 
species  may  be  looked  for  somewhere  in  the  direction  here  at- 
tempted to  be  followed. 

Conclusions  of  any  kind  will  scarcely  be  reached,  either  by 
anatomists  who  neglect  specific  and  generic  characters,  or,  secondly, 
by  systematists  who  in  like  manner  neglect  internal  structure. 
Such  will  never  perceive  the  system  of  nature.* 

ANALYSIS   OF  THE   SUBJECT. 

I.  Relations  of  allied  genera. 

First :  in  adult  age. 

Second  :  in  relation  to  their  development. 

a.  On  exact  parallelism. 

/8.  On  inexact  or  remote  parallelism. 

y.  On  parallelism  in  higher  groups. 

8.  On  the  extent  of  parallelisms. 

II.  Of  retardation  and  acceleration  in  generic  characters. 
First :  metamorphoses  in  adult  age. 

a.  The  developmental  relations  of  generic  and  specific  char- 
acters. 


*  It  might  seem  incredible  that  either  class  should  systematize  with  confidence, 
yet  a  justly  esteemed  author  writes  even  at  the  present  day,  "  However,  there  is 
scarcely  a  systematist  of  the  present  day  who  does  not  pay  m.ore  or  less  attention  to 
anatomical  characters,  in  establishing  the  higher  groups!"  (The  italics  are  our 
own.)  As  though  a  system  were  of  any  value  which  is  not  based  on  the  whole  struct- 
ure^  and  as  though  loxcer  groups  were  only  visible  in  external  characters ;  in  a  word, 
as  though  external  (muco-dermal,  dental,  etc.)  characters  were  not  "  anatomical " ! 


42  GENERAL  EVOLUTION. 

y8.  Probable  cases  of  transition. 
y.  Ascertained  cases  of  transition. 
Second  :  earlier  metamorphoses. 

8.  The  origin  of  inexact  parallelisms. 

III.  Eelations  of  higher  groups. 

a.  Of  homologous  groups. 

p.  Of  heterology. 

y.  Of  mimetic  analogy. 

IV.  Of  natural  selection. 

a.  As  affecting  class  and  ordinal  characters. 
p.  As  affecting  family  characters. 
y.  As  affecting  generic  characters. 
8.  As  affecting  specific  characters. 
c.   On  metaphysical  species. 

V.  Of  epochal  relations. 

The  laws  which  have  regulated  the  successive  creation  of  or- 
ganic beings  will  be  found  to  be  of  two  kinds,  as  it  appears  to  the 
writer.  The  first,  that  which  has  impelled  matter  to  produce 
numberless  ultimate  types  from  common  origins ;  second,  that 
which  expresses  the  mode  or  manner  in  which  this  first  law  has 
executed  its  course,  from  its  commencement  to  its  determined 
end,  in  the  many  cases  before  us. 

That  a  descent,  with  modifications,  has  progressed  from  the 
beginning  of  the  creation,  is  exceedingly  probable.  The  best 
enumerations  of  facts  and  arguments  in  its  favor  are  those  of 
Darwin,  as  given  in  his  various  important  works,  *'The  Origin  of 
Species,"  etc.  There  are,  however,  some  views  respecting  the 
laws  of  development  on  which  he  does  not  dwell,  and  which  it  is 
proi^osed  here  to  point  out. 

In  the  first  place,  it  is  an  undoubted  fact  that  the  origin  of 
genera  is  a  more  distinct  subject  from  the  origin  of  species  than 
has  been  supposed. 

A  descent  with  modification  involves  continuous  series  of  or- 
ganic types  through  one  or  many  geologic  ages,  and  the  co-exist- 
ence of  such  parts  of  such  various  series  at  one  time  as  the  law  of 
mutual  adaptation  may  permit. 

These  series,  as  now  found,  are  of  two  kinds :  the  uninter- 
rupted line  of  specific,  and  the  same  uninterrupted  line  of  generic 
characters.  These  are  independent  of  each  other,  and  have  not, 
it  appears  to  the  writer,  been  developed  pari  passu.    As  a  general 


ON   THE   ORIGIN   OF   GENERA.  43 

law,  it  is  proposed  to  render  highly  probable  that  the  same  specific 
form  has  existed  through  a  succession  of  genera,  and  perhaps  in 
different  epochs  of  geologic  time. 

With  regard  to  the  first  law  of  development,  as  above  proposed, 
no  one  has  found  means  of  discovering  it,  and  perhaps  no  one  ever 
will.  It  would  answer  such  questions  as  this  :  What  necessary- 
coincidence  of  forces  has  resulted  in  the  terminus  of  the  series  of 
fishes  in  the  perches  as  its  most  specialized  extreme ;  or,  of  the 
Batrachia,  in  the  fresh- water  frogs  as  its  ultimum ;  or,  of  the 
thrushes,  among  birds,  as  their  highest  extreme  :  in  a  word,  what 
necessity  resulted  in  man  as  the  crown  of  the  mammalian  series, 
instead  of  some  other  organic  type  ?  Our  only  answer  and  law  for 
these  questions  must  be,  the  will  of  the  Creator. 

The  second  law,  of  modes  and  means,  has  been  represented  to 
be  that  of  natural  selection,  by  Darwin.  This  is,  in  brief,  that  a 
disposition  to  a  general  variation  on  the  part  of  species  has  been 
met  by  the  greater  or  less  adaptation  of  the  results  of  such  varia- 
tion to  the  varying  necessities  of  their  respective  situations.  That 
the  result  of  such  conflict  has  been  the  extinction  of  those  types 
that  are  not  adapted  to  their  immediate  or  changed  conditions, 
and  the  preservation  of  those  that  are. 

In  determining  those  characters  of  plants  and  animals  which 
constitute  them  what  they  are,  we  have,  among  others  of  higher 
import,  those  which  constitute  them  species  and  those  which  con- 
stitute them  genera.  What  we  propose  is  :  that,  of  the  latter, 
comparatively  very  few  in  the  whole  range  of  animals  and  plants 
are  adaptations  to  external  needs  or  forces,  and  of  the  former  a 
large  proportion  are  of  the  same  kind.  How,  then,  could  they  owe 
their  existence  to  a  process  regulated  by  adaptation  ? 

Darwin  is  aware  of  these  facts  to  some  degree,  but,  as  already 
said,  he  does  not  dwell  on  them.  Where  he  does,  he  does  not  at- 
tempt to  account  for  them  on  the  principle  of  natural  selection. 

There  are,  it  appears  to  us,  two  laws  of  means  and  modes  of 
development :  I.  The  law  of  acceleration  and  retardation.  II. 
The  law  of  natural  selection. 

It  is  my  purpose  to  show  that  these  propositions  are  distinct, 
and  not  one  a  part  of  the  other  :  in  brief,  that,  while  natural  selec- 
tion operates  by  the  ^'preservation  of  the  fittest,"  retardation  and 
acceleration  act  without  any  reference  to  '^  fitness"  at  all;  that, 
instead  of  being  controlled  by  fitness,  it  is  the  controller  of  fitness. 
Perhaps  all  the  characteristics  supposed  to  mark  generalized  groups 


44  GENERAL  EVOLUTION. 

from  genera  up  (exceiDting,  perhaps,  families)  have  been  evolved 
under  the  first  mode,  combined  with  some  intervention  of  the  sec- 
ond, and  that  specific  characters  or  species  have  been  evolved  by  a 
combination  of  a  lesser  degree  of  the  first  with  a  greater  degree  of 
the  second  mode. 

I  propose  to  bring  forward  some  facts  and  propositions  in  the 
present  essay  illustrative  of  the  first  mode. 

I.    OJT  THE   KELATIOXS   OF   NEAKLY   ALLIED   GENERA. 

First.  The  writer's  views  of  the  relations  of  genera  have  al- 
ready been  given  at  the  close  of  an  *' Essay  on  the  Cyprinoid 
Fishes  of  Pennsylvania."*  It  is  easy  enough  to  define  isolated 
genera  which  have  few  immediate  afiines  ;  but  among  extensive 
series  of  related  forms  the  case  is  different.  One  principle,  how- 
ever, pervades  the  conception  and  practice  of  all  zoologists  and 
botanists,  which  few  take  pains  to  analyze  or  explain.  It  is 
simply  that  they  observe  a  successional  relation  of  groups,  by 
which  they  pass  from  one  type  of  structure  to  one  or  several  other 
types,  and  the  presence  or  absence  of  the  steps  in  this  succession 
they  regard  as  definitions  of  the  genera. 

It  is  true  that  the  reader  will  often  find  introduced  into  diag- 
noses of  genera  characters  which  indicate  nothing  of  this  sort.  It 
is  often  necessary,  indeed,  to  introduce  characters  which  are  not 
peculiar  to  the  genus  characterized,  for  the  sake  of  distinguishing 
it  from  similar  ones  of  other  series,  but  this  only  in  an  imperfect 
state  of  the  record.  Moreover,  the  ability  of  the  writer  to  distin- 
guish genera  being  thus  tested,  he  too  often  fails  by  introducing 
family  and  specific  characters,  or  by  indulging  in  an  unnecessary 
redundancy.  In  general,  it  may  be  said  that  adjacent  genera  of 
the  same  series  differ  from  each  other  by  but  a  single  character  ; 
and,  generally,  that  the  more  remote  differ  by  characters  as  numer- 
ous as  the  stages  of  their  remove. 

It  is  precisely  as,  among  the  inorganic  elements,  we  pass  from 
the  electro-negative,  non-oxidizing  extreme  of  the  halogens,  with 
fluorine  as  the  extreme,  to  the  electro-positive,  violently  oxidizing 
extreme  of  the  alkaline  metals,  whose  extreme  is  potassium,  by 
steps  whose  relative  position  is  measured  or  determined  first  by 
these  tests ;  and  as  these  steps  have  each  their  included  series  of 

*  "Trans.  Amer.  Philos.  Soc,"  1866,  from  "Proc.  Acad.  Nat.  Sci.,"  Phil.,  1859, 
p.  332. 


ox  THE  ORIGm  OF   GENERA.  45 

bodies,  characterized  by  tlieir  successive  relations  on  the  lower 
level  of  a  subordinate  range  of  characters.  This  principle  is  dis- 
tinctly admitted  by  many  zoologists,*  those  who  deny  it  generally 
failing  to  perceive  it  because  they  attempt  to  gauge  a  major  scale 
by  characters  which  are  really  the  test  of  one  or  all  of  the  subordi- 
nate or  included  scales.  It  holds  true  of  most  of  the  groups  of 
organic  beings ;  thus  the  class  is  a  scale  of  orders,  the  order  of 
tribes.  I  will  not  now  say  that  the  tribe  is  a  scale  of  families,  as 
the  case  is  here  much  modified  ;  but  what  is  chiefly  to  be  consid- 
ered in  this  essay  is,  that  the  family  is  composed  of  one  or  several 
scales  of  genera. 

Second.  Now,  the  more  nearly  allied  genera  are,  the  more 
surely  will  these  generic  steps  be  found  to  fall  into  the  direct  line 
of  the  steps  of  the  development  of  the  highest,  or  that  with  the 
longest  scale,  the  former  being  truly  identical  with  the  latter  in 
generic  characters.  Less  allied  genera  will  offer  an  inexact  or  in- 
complete imitation  of  such  identity — some  additional  character 
being  present  to  disturb  it.  Such  genus  belongs  to  another 
series,  characterized  by  the  disturbing  feature,  whose  members, 
however,  l)ear  to  each  other  the  relation  claimed  above  for  such. 

The  relation  of  genera,  which  are  simply  steps  in  one  and  the 
same  line  of  development,  may  be  called  exact  parallelism ^  while 
that  of  those  where  one  or  more  characters  intervene  in  the 
maturity  of  either  the  lower  or  higher  genus,  to  destroy  identity, 
may  be  called  incomplete  parallelism. 

The  latter  relation  has  been  dwelt  on  by  von  Baer,  Agassiz,  and 
other  writers,  but  none  have  accepted  the  existence  of  exact  paral- 
lelism, or  seen  its  important  relation  to  the  origin  of  genera. 

Third.  That  the  lowest  or  most  generalized  terms  or  genera 
of  a  number  of  allied  series  will  stand  to  each  other  in  a  relation 
of  exact  parallelism.  That  is,  if  we  trace  each  series  of  a  number, 
up  to  its  lowest  or  most  generalized  genus,  the  latter  together  will 
form  a  series,  similar  in  kind  to  each  of  the  sub-series  ;  i.  e.,  each 
genus  will  be  identical  with  the  undeveloped  conditions  of  that 
which  progresses  the  farthest,  in  respect,  of  course,  to  the  char- 
acters which  define  it  as  a  series. 

Those  characters  of  the  skeleton  which  we  are  accustomed  to 
call  embryonic  are  only  so  because  they  relate  to  the  develop- 

*  Prof.  Bronn,  in  his  "  Classen  u.  Ordnungen  des  Thierreiches,"  has  everywhere 
a  chapter  on  "  Die  aufsteigende  Rcihe"  ("the  ascending  scale"). 


46  GENERAL  EVOLUTION. 

mental  succession  witnessed  in  animals  at  the  present  time. 
Characters  not  so  called  now  were  probably  as  much  so  at  one 
period  now  passed.  Hence  embryonic  characters  of  the  bony 
system  do  not,  as  I  have  often  had  occasion  to  observe,  charac- 
terize the  types  of  the  highest  rank,  but  only  subordinate  divis- 
ions of  them.  Thus  the  elasmobranchs  are  i:)robably  rejoressed 
forms  of  groups  of  a  really  higher  grade  than  the  bony  fishes,  or 
teleostei,  which  may  be  known  to  us.  In  their  early  presence  in 
the  geologic  series  we  have  evidence  of  the  first  beginning  of  a 
higher  type. 

In  the  same  manner  it  has  been  discovered  that  the  molecular 
aggregation  of  the  elementary  substances  does  not  characterize 
their  highest  or  most  distinct  series,  but  rather  the  substances 
themselves  within  the  group  or  family  to  which  they  belong. 
The  gaseous,  liquid,  and  solid  molecular  conditions,  being  charac- 
ters distinguishing  otherwise  allied  substances  in  the  same  way 
morphologically  (we  can  not  say  yet  developmen tally),  as  the  car- 
tilaginous, osseous,  and  exostosed  or  dermosseous  characters  dis- 
tinguish otherwise  nearly  allied  genera. 

The  *^family"  group  embraces  one  or  many  of  such  series. 
If  we  trace  the  series  in  scA^eral  families  to  their  simplest  or  most 
generalized  terms  or  genera,  and  compare  them,  we  will  not  find 
the  relation  to  be  one  of  exact  j)arallelism  in  the  series  of  the 
**  order,"  so  far  as  our  present  knowledge  extends,  but,  in  a  devel- 
oj)mental  sense,  one  of  divergence  from  the  commencement. 

If  we  could  know  the  simplest  known  terms  or  family  charac- 
ters of  a  number  of  groups  of  families,  or  *^  orders,"  we  would 
probably  find  them  to  represent  a  series  of  exact  parallelism, 
though  to  find  such  simplest  terms  we  must  go  far  into  past 
periods,  since  the  higher  the  group  the  more  extensive  the  range 
of  its  character,  and  the  less  likely  to  be  found  unmixed  with  ad- 
ditions and  extensions,  in  modern  times. 

Finally,  the  series  of  classes  is  in  the  relation  of  the  essential 
characters  of  the  same,  as  expressed  in  their  now  extinct,  most 
generalized  and  simple  representatives,  also  one  of  "  exact  paral- 
lelism.'' 

a.  Examples  of  Exact  Parallelism,^ 

1.  As  an  example  we  may  take  the  genus  Trachycephalus 
{Batrachia  anurd).     Nearly   allied   to   it  is    the   genus   Osteo- 

*  In  generic  series. 


ON  THE   ORIGIN   OF   GENERA.  47 

cephalus,  wliicli  differs  in  the  normal  exostosis  of  the  cranium 
not  involving  the  derm,  as  in  the  former.  Close  to  this  is 
Scytopis,  where  the  fully  ossified  cranium  is  not  covered  by  an 
exostosis.  Next  below  Scytopis  is  Hyla,  where  the  upper  surface 
of  the  cranium  is  not  ossified  at  all,  but  is  a  membranous  roof 
over  a  great  fontanelle.  Still  more  imperfect  is  Hylella,*  which 
differs  from  Hyla  in  the  absence  of  vomerine  teeth.  Now,  the 
genus  Trachycephalus,  after  losing  its  tail  and  branchiae,  pos- 
sesses all  the  characters  possessed  by  the  genera  Hylella  and  Hyla, 
either  at  or  just  before  the  mature  state  of  the  latter,  as  the 
ethmoid  bone  is  not  always  ossified  in  advance  of  the  parietals. 
It  soon,  however,  becomes  a  Scytopis,  next  an  Osteocephalus, 
and  finally  a  Trachycephalus.  It  belongs  successively  to  these 
genera,  for  an  exhaustive  anatomical  examination  has  failed  to 
reveal  any  characters  by  which,  during  these  stages,  it  could  be 
distinguished  from  these  genera. 

Now,  it  would  be  a  false  comparison  to  say  that  the  young  of 
Trachycephalus  was  identical  with  the  genus  Agalychnis,  which 
in  truth  it  resembles,  because  that  genus  is  furnished  with  one 
other  character — the  presence  of  a  vertical  pupil — and  belongs  to 
another  series  in  consequence,  which  is  represented  as  yet,  with 
our  present  imperfect  knowledge — or  perhaps  imperfect  fauna — 
by  three  genera  only. 

2.  The  lowest  type  of  the  near  allies  of  our  common  fresh- 
water frogs  is  the  genus  Eanula,  where  the  prefrontal  bones  are 
narrow  strips  on  each  side  the  ethmoid  cartilage  ;  the  ethmoid 
cartilage  itself  entirely  unossified  above,  and  the  vomerine  teeth 
very  few  and  on  a  small  elevation.  There  are  two  species,  R. 
affinis  and  R.  palmipes.\  The  other  species  have  the  ethmoid 
cartilage  ossified  above,  at  least  beneath  the  extremities  of  the 
frontoparietals. 

Those  of  the  latter  most  like  Eanula  possess  the  same  type  of 
narrow  prefrontals,  separated  by  a  broad  area  of  cartilaginous 
ethmoid,  and  fasciculi  of  teeth.  Of  this  type  is  Rana  delalandii, 
and  probably  R.  porosissima,  Steind.,  of  the  South  Ethiopian 
region.  Other  species  of  the  same  type  extend  their  vomerine 
patches  into  lines  ;  such  are  R.  mascariensis,  R.  fasciata,  R. 
oxyrhynchus,  R.  grayi,  and  other  South  African  species. 

*  I  refer  to  H.  carnea  m.,  not  having  Reinhardt  and  Liitken's  type  of  this  genus, 
f  These  species  are  now  believed  to  be  identical,  but  three  others  have  been  dis- 
covered (1886). 


48  GENERAL  EYOLUTION". 

The  prefrontals  are  subtriangular,  and  approacli  eacli  other 
more  or  less  in  the  numerous  species  of  North  America  and  of 
the  Regio  Paleearctica,  while  generally  the  vomerine  teeth  are  in 
fascicles  or  yery  short  series.  In  the  -Ethiopian  Rana  fuscigula 
the  prefrontals  unite  on  the  median  line,  roofing  over  the  ethmoid 
cartilage  and  reducing  it,  while  the  vomerine  teeth  are  in  very 
short  lines. 

In  the  species  of  the  Palaeotropical  region,  Rana  tigrina,  R. 
vittigera,  R.  cyanophlyctisy  R.  grimniens,  R.  liexadactyla,  R. 
corrugata,  R.  ehrenhergii,  R»  gracilis,  and  the  Ethiopian  R.  occi- 
pitalis, the  prefrontals  not  only  unite  solidly  (the  suture  remain- 
ing on  the  median  line),  but  extend  and  closely  fit  to  the  fronto- 
parietals.    The  vomerine  patches  have  lengthened  out  into  series. 

Now,  the  young  of  the  latter  type  of  Eana  (I  take  as  an  ex- 
ample the  R.  tigrina,  one  of  the  most  abundant  and  largest  of 
Indian  frogs)  presents  the  subtriangular  prefrontals  neither  in 
contact  with  each  other  or  with  the  frontoparietals,  and  the 
vomerine  series  is  much  reduced ;  in  fact,  it  belongs  in  all 
respects  to  the  Palsearctic  grouj).  I  have  not  examined  younger 
specimens,  but  have  no  doubt  they  are  like  those  of  the  Palse- 
arctic ;  which  are,  in  their  young  stage,  precisely  of  the  type 
of  the  Ethiopian  Rana,  with  fasciculate  teeth  like  the  young  of 
those  of  the  same  region  with  teeth  in  series,  since  the  prefrontals 
are  still  more  reduced,  becoming  linear.  Finally,  the  first  stage 
of  the  Nearctic  Rana,  after  losing  the  larval  tail,  is  the  genus 
Ranula,  having  linear  prefrontals,  minute  vomerine  teeth,  and 
the  ethmoid  ring  cartilaginous  above. 

These  points  of  structure  are  of  generic  quality,  but  I  have 
not  regarded  any  group  as  sufficiently  defined  to  be  so  regarded, 
except  Ranula,  as  the  adults  of  some  species  appear  not  to  be  con- 
stant in  possessing  them.  Thus  a  very  large  Rana  catesleyana 
sometimes  exhibits  prefrontals  in  contact  on  the  median  line, 
while  it  is  difficult  to  say  whether  R.  areolata  of  North  America 
is  of  the  Nearctic  type  so  much  as  of  the  Ethiopian.  Neverthe- 
less, the  groups  are  generally  quite  geographically  restricted. 

3.  A  similar  relation  exists  between  the  genera  Hyperolius, 
Staurois,  and  Heteroglossa  in  respect  to  the  prefrontal  bones  and 
the  separation  of  the  outer  metatarsi,  and — 

4.  Between  Ixalus,  Rhacophorus,  and  Polypedates  also,  in 
reference  to  vomerine  teeth,  bifurcation  of  last  phalange,  and 
dermoossification  of  the  cranium. 


ON  THE   ORIGm  OF   GENERA.  49 

5.  When  the  larvae  of  certain  salamanders  (Spelerpes)  possess 
branchiae,  they  also  lack  one  digit  of  the  hind  foot,  also  the  max- 
illary, nasal,  and  prefrontal  bones,  and  exhibit  a  broad  continuous 
palatopterygoid  arch,  in  close  contact  with  the  parasphenoid. 
The  prootic  is  separated  from  the  exoccipital  by  a  membranous 
space,  and  the  exoccipitals  themselves  are  not  yet  united  above 
the  foramen  magnum.  There  is  at  the  same  time  a  series  of 
splenial  teeth.  Both  ceratohyals  are  confluent,  the  posterior  is 
present,  and  there  are  but  three  superior  hyoid  arches.  After 
they  lose  the  branchiae,  the  hinder  foot,  which  has  four  toes  only 
for  a  time,  gradually  adds  another  at  first  rudimental  digit,  in  the 
Mexican  species  ;  in  most  North  American  species  the  fifth  digit 
appears  at  an  early  larval  stage.  Five  digits  are  finally  present  in 
all  Spelerpes. 

We  have  thus  four  combinations  of  the  above  characters,  at 
different  periods  of  the  life  history  of  certain  (but  not  of  all)  of 
the  species  of  Spelerpes.  There  exist  four  permanent  series  of 
species  or  genera,  equivalent  to  these  stages.  The  well-known 
^^perennibranchiate"  J^ecturus  is  nearly  identical  with  the  first, 
Batrachoseps  with  the  second,  the  half-toed  Spelerpes  with  the 
third,  and  the  typical  Spelerpes  is  the  last. 

In  one  character  of  generic  value  only  do  I  find  that  Necturus 
differs  from  the  early  larval  Spelerpes.  It  closes  the  premaxillary 
fontanelle  with  which  it  commences,  by  an  approximation  of  the 
premaxillary  spines,  but  not  by  a  sutural  union,  as  takes  place  in 
Amblystoma.  It  thus,  in  this  one  point,  advances  a  stage  beyond 
the  condition  to  which  Spelerpes  attains,  though  it  may  be  a 
question  whether  such  a  closure  without  union  should  not  be 
classed  among  the  specific  characters  by  which  iV.  maculatus  dif- 
fers from  the  young  of  the  various  Spelerpes,  as  they  do  from 
each  other.  Characters  of  the  latter  kind  are  the  following  :  in 
N.  maculatus  the  frontals  are  more  deeply  emarginate  behind  ;  it 
has  little  or  no  ala  on  the  inferior  keel  of  the  caudal  vertebrae, 
which  is  prominent  in  Spelerpes  larvae. 

It  may  be  that  the  parallelism  in  the  case  of  Spelerpes  is  inex- 
act by  one  character,  and  that  a  strictly  developmental  one  ;  or 
it  may  be  regarded  otherwise.* 

6.  It  is  well  known  that  the  Cervidae  of  the  Old  World  devel- 


*  Necturus  differs  from  these  larvas  by  another  and  more  important  character, 

viz.,  the  presence  of  the  os  intercalare. 
4 


50  GENERAL  EYOLUTIOK 

op  a  basal  snag  of  the  antler  (see  Cuvier,  "  Ossem.  Fossiles"; 
Gray,  "  Catal.  Brit.  Mus.")  at  the  third  year ;  a  majority  of  those 
of  the  'New  World  (genera  Cariaciis,  Subulo)  never  develop  it 
except  in  ^'abnormal"  cases  in  the  most  vigorous  maturity  of  the 
most  northern  Cariacus  (C.  virginianus) ;  while  the  South  Ameri- 
can Subulo  retains  to  adult  age  the  simple  horn  of  the  second 
year  of  Cervus. 

Among  the  higher  Cervidae,  Rusa  and  Axis  never  assume  char- 
acters beyond  an  equivalent  of  the  fourth  year  of  Cervus.  In 
Dama  the  characters  are  on  the  other  hand  assumed  more  rapidly 
than  in  Cervus,  its  third  year  corresponding  to  the  fourth  of  the 
latter,  and  the  development  in  after  years  of  a  broad  plate  of 
bone,  with  points,  being  substituted  for  the  addition  of  the  corre- 
sponding snags,  thus  commencing  another  series. 

Returning  to  the  American  deer,  we  have  Blastocerus,  whose 
antlers  are  identical  with  those  of  the  fourth  j^ear  of  Cariacus. 

Now,  individuals  of  the  genus  Cervus  of  the  second  year  do 
not  belong  to  Subulo,  because  they  have  not  as  yet  their  mature 
dentition.  Rusa,  however,  is  identical  with  those  Cervi  whose 
dentition  is  complete  before  they  gain  the  antlers  of  the  fifth 
year.  When  the  first  trace  of  a  snag  appears  on  one  beam  of 
Cariacus  virginianus,  the  dentition  includes  the  full  number,  but 

there  remain  -  milk  molars  much  worn  and  ready  to  be  shed. 

Perhaps  the  snag  is  developed  before  these  are  displaced.  If  so, 
the  Cariacus  is  never  a  Subulo,  but  there  can  be  little  doubt  that 
the  young  Blastocerus  belongs  to  that  genus  before  its  adult  char- 
acters appear. 

7.  Leidy  states  *  that  certain  Perissodactyl  remains,  contain- 
ing a  foot  of  a  horse,  contained  the  teeth  of  a  genus,  Protohippus, 
which  has  the  permanent  teeth  of  Equus,  and  the  deciduous 
dentition  of  Anchitherium.  He  observes  :  *^The  deciduous  and 
permanent  dentitions  of  both  these  genera  are  alike ;  therefore 
the  new  genus  is  in  early  life  an  Anchitherium,  and  later  in  life  a 
true  horse."  This  is  therefore  a  case  of  exact  parallelism,  always 
providing  that  the  Protohippus  has  not  added  to  its  immature 
equine  characters  others  in  other  parts  of  the  body,  which  in- 
validate the  identity.  In  the  latter  case  it  will  still  be  an  inter- 
esting example  of  the  *^ inexact  parallelism."  \ 

*  "Proceed.  Acad.  Xat.  Sci,"  1858,  p.  7. 

f  This  is  not  a  proper  example  of  parallelism  if,  as  some  zoologists  believe,  the 


ON  THE   ORIGIN   OF  GENERA.  51 

8.  It  is  well  known  that  the  Cephalopoda  form  a  number  of 
series  of  remarkable  regularity,  the  advance  being,  in  the  first 
place,  in  the  complication  of  the  folds  of  the  external  margins  of 
the  septa,  and,  in  the  second  place,  in  the  degree  of  involution  of 
one  or  both  extremities  of  the  shell  to  the  spiral ;  third,  in  the 
position  of  the  siphon. 

Alpheus  Hyatt,  in  an  important  essay  on  this  subject,* 
points  out  that  the  less  complex  forms  are  in  many  cases  iden- 
tical with  the  undeveloped  conditions  of  the  more  complex. 
He  says  :  ^^  There  is  a  direct  connection  between  the  position  of 
a  shell,  in  the  completed  cycle  of  the  life  of  this  order,  and  its 
own  development.  Those  shells  occujoying  the  extremes  of  the 
cycle"  (in  time),  ^Hhe  polar  forms,  being  more  embryonic  than 
the  intermediate  forms,  f  The  first  epoch  of  the  order  is 
especially  the  era  of  rounded,  and,  in  the  majority  of  the  spe- 
cies, of  unornamented  shells  with  simple  septa ;  the  second  is 
the  era  of  ornamentation,  and  the  septa  are  steadily  complicat- 
ing ;  in  the  third  the  complication  of  the  septa,  the  ornamen- 
tation, and  the  number  of  species,  about  twice  that  of  any 
other  epoch,  all  combine  to  make  it  the  zenith  of  development 
in  the  order ;  the  fourth  is  distinguishable  from  all  the  preced- 
ing as  the  era  of  retrogression  in  the  form,  and  partially  in  the 
septa. 

**  The  four  periods  of  the  individual  are  similarly  arranged, 
and  have  comparable  characteristics.  As  has  been  previously 
stated,  the  first  is  rounded  and  smooth,  with  simple  septa ;  the 
second  tuberculated,  and  the  septa  more  complicated  ;  the  third 
was  the  only  one  in  which  the  septa,  form,  and  ornamentation 
simultaneously  attained  the  climax  of  individual  complication ; 


deciduous  or  temporary  dentition  is  not  a  remnant  of  the  primitive  dentition,  but  is 
a  later  product  of  mammalian  evolution.  If  it  be  a  case  of  parallelism,  it  is  inexact, 
because  the  genus  Protohippus  was  discovered  by  the  writer  to  have  three  toes, 
while  Equus  has  but  one. 

*  "  Memoirs  Boston  Soc.  Nat.  Hist.,"  1866,  p.  193. 

f  He  adds  here  :  "  Although  in  regard  to  geological  sequence  and  structural  po- 
sition one  of  the  extremes  must  be  of  higher  geological  rank."  The  "  highest "  ex- 
treme will  be  of  higher  geological  rank,  according  to  the  complexity  of  structure  and 
length  of  developmental  scale,  whether  it  come  at  the  middle  or  end  of  the  history 
of  the  class  in  time.  If,  as  has  been  the  case,  so  far  as  known,  a  decline  has  termi- 
nated the  history  of  a  class,  its  later  forms  are  zoologically  loicer  than  its  older 
ones.  Hence  the  adjective  high  is  only  appropriate  to  types  of  the  latter  kind^ 
when  used  as  synonymous  with  extreme. 


52  .     GENERAL  EVOLUTION. 

the  fourth,  when  amounting  to  anything  more  important  than 
the  loss  of  a  few  ornaments,  was  marked  by  a  retrogression  of  the 
whorl  to  a  more  tabular  aspect,  and  by  the  partial  degradation  of 
the  septa." 

I  will  here  quote  an  entirely  antagonistic  statement  of 
Bronn's,*  as  follows  :  **  In  the  development  of  lamellibranchiate 
mollusks  it  is  not  possible  to  estimate  the  successional  changes  of 
one  genus  by  those  of  another,  though  nearly  related  ;  so  diverse 
are  the  most  significant  relations  in  the  manner  of  progress  among 
nearest  allies.  Therefore,  embryologic  indications  are  throughout 
useless  in  classification,  and  it  is  necessary  to  keep  carefully  se^oa- 
rate  the  statements  of  observations  on  development  of  a  given 
species,  and  not  transfer  such  facts  to  the  history  of  another  spe- 
cies for  the  purjDose  of  completing  it.  We  can  not  even  range 
these  histories  in  conformity  with  family  groups."  For  us  this 
statement,  though  no  doubt  largely  true,  is  an  indication  of  im- 
perfection— first,  of  knowledge  of  true  affinities  of  recent,  but 
esi^ecially  of  extinct  adults,  and,  second,  of  imperfection  of  knowl- 
edge of  development.  The  position  api^ears  to  be  based  on  nega- 
tive evidence,  while  the  opposing  can  and  does  stand  on  nothing 
but  positive. 

/?.  Examples  of  the  Inexact  Parallelism. 

1.  The  genera  of  the  batrachian  family  Scaphiopodidae  form 
a  series  of  steps  differing  a  little  more  than  as  repressions  or  joer- 
manent  primary  conditions  in  the  development  of  the  highest,  f 
Thus  two  of  the  genera,  which  are  North  American,  maintain 
their  tubae  eustachii  and  tympanum  through  life,  while  three 
European  lose  them  at  an  early  period.  J;  The  three  European 
genera  also  advance  beyond  the  larval  character  of  the  Ameri- 
can in  the  ossification  of  the  basis  of  the  xiphisternum  into  a 
broad  style.  Thus  we  have  two  series  established,  which  differ 
only  in  the  two  characters  named.  Each  shows  its  develop- 
mental steps  in  a  similar  manner,  the  European  series  extending 
further ;  thus  : 

*  "  Classen  u.  Ordnungen  des  Thierreichs,"  iii,  p.  445. 

f  See  "Journal  Academy,"  Philadelphia,  1866,  on  Areifera. 

X  According  to  Bruch  and  Tschudi,  in  Pelobates.  I  have  found  traces  of  the 
eustachian  diverticula,  in  a  tailed  Pelobates  fuscus,  whose  body  measured  1  in.  4  lin., 
from  Mus.  Peabody  Institute,  Salem,  Mass. 


ON   THE   ORIGIN   OF   GENERA.  53 

European,  North  American, 

1.  Temporal  fossa  over  arched. 

Oultripes.  *  * 

Temporal  roof  not  ossified. 

2.  Fronto-parietal  bones  ossified,  involving 

derm. 

Pelobates.  Scapliiopns. 

3.  Fronto-parietals  ossified,  distinct  from 

derm. 

*  *  (Unknown.)  *  * 

4.  Fronto-parietals    not    ossified,    distinct 

from  derm. 

Didocus.  Spea. 

In  this  case  Didocus  can  not  be  said  to  be  identical  as  a  genus 
with  an  undeveloped  stage  of  Oultripes,  since,  while  the  cranium 
of  the  latter  is  in  the  condition  of  Didocus,  it  bears  a  long  tail, 
and  the  limbs  are  but  little  developed.  Nor  is  Didocus  identical 
with  the  undeveloped  condition  of  Pelobates,  since  both  cranium 
and  limbs  of  the  latter  are  developed  before  the  tail  is  absorbed. 
Nor  is  Pelobates  identical  with  the  undeveloped  condition  of  Oul- 
tripes, since,  while  the  cranium  of  the  latter  is  that  of  the  former, 
the  limbs  and  tail  are  still  larval.  The  same  relations  exist  be- 
tween the  other  members  of  the  family;  The  genus  Scaphiopus 
is  not  an  undeveloped  form  of  Pelobates  as  to  its  auditory  organs, 
for,  when  the  latter  is  identical  with  the  former  in  this  respect,  it 
bears  otherwise  entirely  larval  characters.  Nor  is  Spea  an  arrested 
Scaphiopus,  the  relation  being  here  precisely  that  between  Dido- 
cus and  Pelobates.  Spea  approaches  more  closely  ah  arrested 
Didocus  in  all  respects,  but  that  when  the  latter  possesses  the  au- 
ditory apparatus  *  of  the  former,  it  is  a  larva  in  limbs  and  tail, 
and  that  it  loses  this  apparatus  before  reaching  the  other  charac- 
ters of  Spea.  The  relations  of  these  genera,  as  compared  with 
those  of  the  Trachycephalus,  Oystignathidse,  and  Bufo  series,  may 
be  represented  as  follows  :  the  lines  represent  the  developmental 
scale  of  each. 

This  is  an  example  of  the  simplest  case  of  inexact  parallelism, 
as  distinguished  from  the  exact  parallelism  or  identity.  As  the 
fauna  of  the  present  period  is  but  a  fragment,  so  the  simple  inex- 


*  The  possession  of  eavum  tympani  and  tuba  Eustachii  in  the  undeveloped  con- 
dition of  this  genus  is  only  assumed  from  its  close  relation  to  Pelobates. 


54 


GENERAL  EVOLUTION". 


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act  is  a  more  frequent  relation  than  the 
exact,  while  the  more  complex  inexact 
relation  is  still  more  common.  The 
greater  the  inexactitude,  the  more  fre- 
quently do  such  parallels  occur  till  we 
have  those  of  the  most  remote  character, 
as,  for  instance,  the  parallelism  between 
the  different  stages  of  the  development 
of  the  mammal,  in  the  structure  of  the 
heart  and  origins  of  the  aorta,  and  the 
existing  classes  of  vertebrates.  The  re- 
lation of  these  facts  to  the  origin  of 
genera  will  be  noted  hereafter. 

It  will  be  borne  in  mind  that  in  the 
Scaphiopodidae  the  generic  types  are 
identical  for  a  long  portion  of  their 
developmental  history.  (See  figures  on 
plate  iv  for  the  representation  of  these 
facts. ) 

2.  In  both  Perissodactylous  and  Ar- 
tiodactylous  Mammalia,  certain  types 
develop  their  family  character  of  ca- 
nines at  the  earliest  appearance  of  den- 
tition, others  not  till  a  comparatively 
late  period  of  life  (Equus),  and  the  ex- 
treme individuals  never  produce  them. 

3.  Among  cetaceans  the  genus  Orca 
maintains  a  powerful  and  permanent 
series  of  teeth,  which  is  an  important 
generic  character.  In  Beluga  the  se- 
ries is  shed  in  old  age,  in  Globiocepha- 
lus,  or  the  Caing  whales,  they  are  shed 
at  middle  age,  while  in  the  Balsenidse, 
of  which  the  absence  of  teeth  is  an  es- 
sential character,  these  organs  are  de- 
veloped and  absorbed  during  fcetal  life 
(Eschricht).  Though  the  condition 
of  the  teeth  is  not  of  systematic  value 
in  the  two  named  intermediate  genera, 
it  is  the  important  feature  in  the  his- 
tory of  progress  to  such  value. 


OE"  THE  ORIGIN  OF   GENERA.  55 

4.  Among  the  tortoises,  the  Testudinidae  rapidly  extend  the 
ribs  into  a  carapace,  which  fits  closely  the  marginal  bones,  while 
equally  early  in  life  the  elements  of  the  sternum  unite  together. 
This  is  also  the  case  with  most  Emydidee  ;  among  whose  genera, 
however,  we  find  the  transitional  scale.  In  Dermatemys  and 
Batagur  the  carapace  is  very  late  in  attaining  its  complete  ossifi- 
cation, while  the  plastron  is  early  finished.  In  Chelydra,  on  the 
other  hand, while  the  carapace  is  even  more  slowly  developed,  the 
plastron  is  never  free  from  its  larval  fontanelles.  In  the  marine 
turtles  neither  plastron  nor  carapace  is  ever  completed,  while 
in  the  Trionychidag  the  marginal  bones  are  also  entirely  unde- 
veloped. 

In  order  that  this  last  illustration  be  a  true  one  for  the  theory 
in  question,  as  applied  to  ihQ  families,  these  developmental  char- 
acters should  be  the  true  distinctive  features  of  these  families  re- 
spectively. This,  as  is  well  known,  they  are  not.  The  Chelo- 
niidse  are  characterized  by  the  form  of  their  anterior  limbs,  which 
is  in  an  adaptive  structure,  while  the  Testudinidae  similarly  are 
distinguished  by  an  extreme  opposite  modification  of  foot-struct- 
ure, adapted  to  an  extreme  difference  of  habit.  Here  there  is  an 
example  of  the  co-working  of  both  laws.  Nevertheless,  we  only 
claim  at  present  to  show  the  developmental  relation  of  genera  of 
the  same  family  and  the  same  series.  This  we  see  among  the 
Emydidae. 

5.  In  the  important  character  of  the  sciitellation  of  the  tarsi 
among  the  Passerine  birds,  the  ^^boot"  appears  early  in  life  in  the 
highest  Oscines,  later  in  the  lower,  and  does  not  ai:)pear  at  all  in 
the  majority.  In  respect  to  the  still  more  important  feature  of 
the  long  posterior  plates  which  appear  very  early  in  most  Oscines, 
in  the  Myiadestes  type  *  they  appear  late,  the  squamse  remaining 
long,  while  the  Clamatores  never  develop  the  plates,  not  advancing 
beyond  the  infantile  squamous  stage. 

6.  It  has  been  shown  by  Falconer  that  the  genera  of  great 
Proboscidians  form  a  remarkably  regular  and  graded  series,  dis- 
tinguished by  their  dentition.  These  are  Dinotherium  Kaup, 
Trilophodon  Falc,  Mastodon  Cuv.,  Pentalophodon  Falc,  Stego- 
don  Falc,  Loxodon  F.  Cuv.,  and  Elephas  Linn.  In  the  first 
there  are  but  two  cross  crests  on  the  third  molars,  and  a  pair  of 
permanent  mandibular  tusks  ;   in  the  second,  three  cross  crests 


*  Baird,  "  Review  of  Birds  of  North  America." 


56  GENERAL  EVOLUTION. 

and  mandibular  tusks  permanent  in  some  males ;  in  the  third, 
four  cross  crests  and  the  mandibular  tusks  variable  ;  in  the  fourth, 
five  cross  crests  on  the  third  molar ;  tusks  unknown.  In  Stego- 
don  the  mandibular  tusks  cease  to  appear,  the  crests  of  the  third 
molar  become  more  numerous,  and  embrace  between  them,  in  the 
bottoms  of  the  valleys,  a  strong  deposit  of  cementum.  In  Loxo- 
don  the  crests  have  the  whole  interspaces  filled  with  cementum, 
while  the  same  thing  holds  in  Elephas,  with  a  greatly  increased 
number  of  cross  crests,  which  become  vertical  laminae.  The  lami- 
nar character  has  become  ap2)arent  from  its  rudimental  condition 
in  Stegodon. 

'Now,  these  are  stages  of  development,  though  not  in  a  con- 
tinuous, single  line.  The  shedding  of  the  inferior  tusks  takes 
place  earlier  and  earlier  in  the  genera  from  Dinotherium,  till 
they  never  appear  in  Stegodon.  The  molar  teeth,  it  is  well 
known,  present,  as  they  succeed  each  other  from  back  to  front, 
a  regularly  increasing  number  of  transverse  crests  in  the  same 
species.  Thus,  in  Trilophodon  oliioticus  the  first  molar  presents 
but  two,  while  the  last  presents  six.  The  last  molars  of  other 
genera  present  a  very  much  increased  number.  What  is  it, 
then,  but  that  the  increased  number  of  crests  in  the  third  molar, 
definitive  of  these  genera,  is  an  acceleration  of  growth ;  the 
fourth  in  Trilophodon  is  structurally  third  in  Mastodon,  and  the 
fourth  of  Mastodon  being  third  in  Pentalophodon  ;  the  fourth 
of  Pentalophodon  becoming  third  in  Stegodon,  and  so  to  the 
end  ?  This  is  confirmed  from  the  proved  fact  of  the  disap- 
pearance of  the  premolars.  They  are  fewer  in  Trilophodon 
than  in  Dinotherium,  and  are  soon  shed ;  they  are  also  early 
shed  in  Mastodon  and  Stegodon  {insig7iis  Falc.  Caut.),  and  are 
not  known  to  exist  in  the  succeeding  types ;  the  acceleration  of 
succession  of  teeth  has  caused  them  to  be  entirely  omitted.  The 
young  tooth  of  Elephas,  moreover,  is  represented  by  a  series  of 
independent  parallel  laminae  at  first,  which,  when  they  unite, 
form  a  series  of  crests  similar  to  the  type  of  the  genus  Mastodon 
and  others  of  the  beginning  of  the  series.  The  deposit  of  cemen- 
tum takes  place  later,  till  the  valleys  are  entirely  filled  up.  Thus 
the  relations  of  this  part  of  the  tooth-structure  in  the  series  are 
also  those  of  the  successional  growth  of  those  of  Elephas,  the  ex- 
treme of  the  series. 

It  would  be  only  necessary  to  show  that  two  distinct  condi- 
tions, in  any  of  these  respects,  occurred  among  the  different  indi- 


ox  THE  ORIGm  OF   GENERA.  57 

viduals  of  the  same  species  of  any  of  tliese  genera,  to  render  a 
hypothesis  of  evolution  a  demonstrated  fact.* 

It  must  be  here  observed  that  great  size  indicates  little  or 
nothing  as  to  zoological  rank.  The  greatest  species  are  often  not 
far  removed  in  affinity  from  the  least ;  thus  there  can  be  but  little 
doubt  that  elephants  are  not  far  removed  from  the  rodents,  and 
the  rhinoceros  is  near  the  cony.  Indeed,  in  the  same  genus  the 
most  extraordinary  diversity  prevails,  for  we  have  a  very  small 
elephant  of  Malta,  and  in  the  Miocene  of  Maryland  a  fin-back 
whale  not  so  large  as  the  new-born  young  of  the  fin-backs  now 
living.  Hence  the  objection  to  the  developmental  hypothesis, 
based  on  the  great  size  of  the  primal  Selachians  and  Ganoids,  has 
but  little  weight. 

7.  Eathke  has  shown .  that  the  arteria  ophthalmica  of  the 
higher  Ophidians  is  originally  a  branch  of  the  arteria  cerebralis 
anterior,  and  that  it  later  forms  a  connection  with  the  arteria 
facialis.  This  connection  increases  in  strength,  while  the  other 
diminishes,  until  finally  its  supply  of  blood  is  derived  from  the 
facialis  instead  of  the  cerebralis. 

Eathke  has  also  shown  that  the  cerebral  origin  of  this  artery 
is  continued  through  life  in  the  three  lowest  suborders  of  the  ser- 
pents, the'Scolecophidia,  Catodonta,  and  Tortricina ;  also  in  the 
next  succeeding  group,  the  Peropoda. 

8.  In  most  serpents  the  left  lung  is  never  developed  ;  in  such 
the  pulmonary  artery,  instead  of  being  totally  wanting,  remains 
as  a  posterior  aorta  bow,  connected  with  the  aorta  by  a  ductus  bo- 
talli ;  serpents  without  left  lung  being  therefore  identical  in  this 
respect  with  the  embryonic  type  of  those  in  which  that  lung 
exists. 

9.  Dr.  Lespes  states  that  the  optic  region  of  the  brain  of  blind 
cave  Coleoptera,  examined  by  him  is  similar  in  structure  to  that 
in  the  blind  larvae  of  Coleoptera,  whose  imagos  j^ossess  visual 
organs. 

10.  t  Those  Saurians  (Uromastix,  etc.),  in  which  the  pre- 
maxillary  region  is  produced  into  a  uniform  cutting  edge,  are 
furnished  during  early  stages  with  a  series  of  premaxillary  teeth, 
which  become  gradually  fused  and  confluent  with  the  alveolar 
margin.     Hence  other  Acrodonts  are  equivalent,  in  this  respect, 

*  This  variability  has  since  been  shown  to  exist  in  species  of  the  M.  angmtidens 
type  (1886). 

\  See  under  section  on  Acceleration  and  Retardation. 


58  GENERAL  EYOLUTIOX. 

to  the  young  of  Uromastix,  etc.  The  same  tiling  occurs  among 
the  Scaroid  and  Labroid  fishes.  In  this  most  natural  family  we 
find  the  majority  of  generic  forms  provided  with  a  normal  com- 
plete dentition  ;  in  others  (Chaerops,  Xiphochilus,  Pseudodax, 
etc.)  the  lateral  teeth  are  gradually  and  normally  replaced  by  a 
more  or  less  cutting  edge  of  the  mandible ;  and  finally,  in  the 
Scarina  and  Odacina,  the  entire  mass  of  teeth  and  jaws  are  coa- 
lesced, forming  a  beak  with  sharp  cutting  edges,  the  single  teeth 
being  still  visible  in  the  true  Scarus,  while  they  have  entirely  dis- 
appeared in  adult  Pseudoscarus  and  Odax.*  Thus,  in  dentition, 
the  adult  Scarus  is  identical  with  not  fully  developed  Odax  ; 
Chaerops,  with  the  teeth  less  confluent,  equals  a  still  younger  stage 
of  Odax,  while  those  with  distinct  teeth  are  tiie  same  in  this  point 
as  the  embryos  of  the  highest — Odax,  etc.  I  venture  to  predict 
that  here  will  be  found  a  long  series  of  exact  parallelism,  in  which 
the  different  genera,  resting  exclusively  on  these  dental  characters, 
will  be  found  to  be  identical  generically  with  the  various  stages 
of  the  successively  most  advanced. 

11.  Prof.  Agassiz  states  that  the  absence  of  ventral  fins  is  char- 
acteristic of  an  embryonic  condition  of  the  Cyprinodont  fishes. 
The  genus  Orestias  does  not  progress  beyond  this  stage  in  this  one 
point.  Probably  the  genus  will  be  found  which  will  only  differ 
from  Orestias  in  the  presence  of  ventral  fins.  If  so,  Orestias  will 
be  identical  with  an  imperfect  stage  of  that  genus,  if,  as  will  prob- 
ably be  the  case,  the  fins  appear  in  the  latter,  after  other  struct- 
ures are  fully  completed. 

yy.  Parallelism  in  Higher  Groups. 

It  is  not  to  be  anticipated  that  the  series  of  genera  exhibiting 
exact  parallelism  can  embrace  many  such  terms,  since  compara- 
tively few  stages  in  the  developmental  condition  of  the  same  part, 
in  the  highest,  would  bring  us  back  to  a  larval  condition,  which, 
as  far  as  we  yet  know,  has  no  exact  parallel  among  existing  genera. 
But  it  is  to  be  believed  that  the  lowest  terms  of  a  number  of  the 
most  nearly  allied  of  such  series  do  of  themselves  form  another 
series  of  exact  parallelisms. 

Thus  exact  parallelism  between  existing  genera  of  mammals 
ceases,  with  all  characters  which  are  larval  or  foetal,  only  prior  to 


*  Giinther  on  Hatteria,  "Philosophical  Transactions,"  186Y,  ii.     I  had  already 
noticed  the  peculiar  development  in  Uromastix,  but  not  published  it. 


ox  THE   ORIGIN   OF  GENERA.  59 

the  assumption  of  the  adult  dentition,  since  among  the  higher 
Mammalia  at  least  we  know  of  no  genus  which,  however  similar  to 
undevelo^Ded  stages  of  the  higher,  never  loses  the  milk  dentition. 
It  is  nevertheless  an  important  fact  that  among  smooth-brained 
mammals,  or  many  of  them,  but  one  tooth  of  the  second  series 
appears  ;  and  inasmuch  as  smooth-brained  forms  of  the  higher 
orders  have  become  extinct,  it  is  not  too  much  to  anticipate  that 
a  type  of  permanent  milk  dentition  will  be  found  among  the  ex- 
tinct forms  of  the  same  high  orders. 

As  an  example  of  exact  parallelisms  in  series  of  series,  I  select 
the  following  : 

1.  In  the  batrachian  family  Cystignathidae  there  are  six  groups 
or  sets  of  genera.  In  the  highest  of  these  we  have  an  ossified  cra- 
nium and  xiphisternum — i.  e.,  in  the  Cystignathi ;  in  the  Pleuro- 
demae  the  cranium  is  not  ossified,  thus  representing  the  Cystigna- 
thi while  incomplete  ;  in  the  Crini^  the  xiphisternum  is  cartilagi- 
nous, as  well  as  the  fronto-parietal  region,  being  an  equivalent  of 
a  still  lower  stage  of  the  Cystignathi.  From  this  simplest  type  we 
can  find  a  rising  series  by  a  different  combination  of  characters  ; 
thus  the  Ceratophydes  add  an  osseous  cranium  to  the  incomplete 
xiphisternum,  while  two  succeeding  groups  diverge  from  each 
other  at  the  start,  the  Pseudes  loosening  the  outer  metatarsus  in 
their  development  to  maturity,  while  the  Hylodes  add  by  degrees 
a  cross-limb  to  the  last  phalange.  The  Ceratophrydes  and  Criniae 
are  stages  in  the  development  of  these  ;  but  neither  one  of  them 
is  a  step  in  the  development  of  the  other.  They  are  measured  by 
adaptive  characters  purely. 

2.  The  whole  suborder  'of  the  Anurous  Batrachia,  to  which 
the  above  family  belongs,  the  Arcifera,  differs  from  the  suborder 
Eaniformia  by  a  character  which  distinguishes  a  primary  stage  of 
growth  of  the  latter  from  its  fully  developed  form.  That  is,  the 
Eaniformia  present,  at  one  period  of  their  development,  a  pair  of 
parallel  or  over-lapping  curved  cartilages,  connecting  the  procora- 
coid  and  coracoid  bones,  which  subsequently  unite  and  become 
a  single,  slender  median,  scarcely  visible  rod,  while  the  bones 
named  expand  and  meet.  The  first  condition  is  the  permanent 
and  sole  systematic  character  of  the  Arcifera.* 

Ohjection. — It  may  be  objected,  by  those  who  have  observed 

*  This  may  be  readily  understood  by  comparing  my  monograph  of  the  Arcifera, 
"Jour.  Ac.  Nat.  Sci.,"  Phil,  1866,  with  Duges's  work,  or  Gegenbaur  and  Parker's 
memoir  on  the  Shoulder-Girdle. 


60  GENERAL  EVOLUTION. 

some  of  these  developmental  relations,  that  they  are  exhibited 
by  certain  single  structures  only,  and  not  by  whole  organisms. 
These  objectors  must  not  forget  that  the  distinctions  of  those 
groujis,  which  alone  we  have  in  one  geological  period  in  a  relation 
of  near  affinity,  exists  in  single  characters  only ;  and  that  it  is 
therefore  infinitely  probable  that  the  higher  groups,  when  we 
come  to  know  their  rejDresentatives  with  the  same  completeness, 
will  prove  to  be  separated  by  single  characters  of  difference  also. 

3.  The  following  table  (pages  63  to  73)  is  introduced  to  illus- 
trate the  relations  of  groups  higher  than  the  preceding.  This  is 
largely  measured  by  the  circulatory  system,  not  only  as  to  the 
class  relations,  but  also  as  regards  orders.  In  its  less  central  por- 
tions it  is,  however,  definitive  of  families  at  times.*  (See  also 
Plate!) 

If  the  reader  will  comjoare  the  history  of  the  development  of 
vertebrates  of  any  class  or  order,  as  those  of  Teleosts  and  the 
lizard  by  Lereboullet,  of  the  snake  and  tortoise  by  Kathke  and 
Agassiz,  and  of  the  bird  and  mammal  by  von  Baer,  he  will  find 
the  most  complete  examples  of  the  inexact  paraTlelism  of  the 
lower  types  with  the  embryonic  stages  of  the  higher.  A  few 
points  are  selected  as  examples,  from  the  histories  included  in  a 
few  of  the  columns  of  the  table,  and  given  at  its  end. 

Similar  parallels  may  be  found  to  exist  in  the  most  beautiful 
manner  between  the  adult  anatomv  and  structure  of  the  uroo^eni- 

*/  CI? 

tal  aj)paratus  within  each  class  of  the  series  taken  separately,  as 
indicating  ordinal  relationship.  This  department  is,  however, 
omitted  for  the  present. 

As  an  example  of  the  homologies  derivable  from  the  circula- 
tory system,  and  of  the  use  of  the  following  table,  I  give  the  fol- 
lowing relations  between  the  types  of  the  origins  of  the  aorta,  f 

The  single  ventricle  of  Teleostei  is  no  doubt  homologous  with 
that  of  Lepidosteus,  and  that  of  Lepidosiren.     The  arteria  vesiccB 

*  This  sketch  is  not  nearly  complete,  but  is  published  in  hopes  of  its  being  use- 
ful to  students.  It  is  compiled  from  the  works  of  Meckel,  Rathke,  Barkow,  Miiller, 
Ilyrtl,  Briicke,  Stannius,  and  others,  in  connection  with  numerous  dissections. 

f  Prof.  Agassiz  ("  Contrib.  Nat.  Hist.  U.  S.,"  i,  p.  285)  states  that  the  ven- 
tricle of  the  Testudinata  "  is  not  any  more  identical  with  the  one  ventricle  of 
fishes  than  with  the  two  ventricles  of  warm-blooded  vertebrata  ;  for  in  fishes  we 
find  only  one  vessel,  the  aorta,  arising  from  it,  while  in  turtles  both  the  ao7'ta  and 
arteria  pulmonalis  start  to'^ether  from  it."  We  think  this  statement,  which,  if  true, 
is  destructive  to  the  asserted  homologies  of  the  circulatory  system,  can  not  be  sub- 
stantiated, for  the  reasons  above  given. 


occ 


cul 


5        m  ao 
Central  Circulatory  System. 


ao— 


Figs.  1,  2,  fish.     Figs.  3,  4,  batracliian.     Fig.  5,  reptile.     Fig.  6,  bird. 

Figs.  7,  8,  human  foetus. 


PLATE   I. 


Figures  and  Diagrams  of  the  circulatory  centers  of  Vertebrata.  Copied  from 
Gegenbaur  and  His,  mostly  enlarged. 

Fig.  1.  Diagram  of  the  arterial  arches  of  a  Fish  (species  not  given). 

Fig.  2.  Head  of  an  embryonic  Teleostean,  with  the  rudiments  of  the  vascular 
system  (diagrammatic). 

Fig.  3.  Heart  and  arterial  trunks  of  a  larva  of  a  Salamander. 

Fig.  4.  Arterial  system  of  the  Frog. 

Fig.  5    Heart  and  arteries  of  an  Ophidian  (Boa). 

Fig.  6.  Diagram  of  the  arterial  system  of  the  adult  Fowl. 

Fig.  7.  Central  circulatory  system  of  Man ;  foetus  of  the  second  month ;  front 
view. 

Fig.  8.  Same  as  Fig.  7,  left  side. 


V,  ventricle  of  heart. 

«,  auricle  of  heart. 

s  V,  sinus  venosus  of  heart. 

b  a,  bulbus  arteriosus  of  heart. 

a  6,  aorta  branchialis. 

1,  2,  3,  4,  5,  arteriae  branchiales. 

V  1,  2,  3,  venae  branchiales. 

ao,  aorta. 

ad,  aorta  dextra  (right). 

a  5,  aorta  sinistra  (left). 

p,  arteria  pulmonalis. 

db,  ductus  botalli. 

ca,  arteria  carotis. 

cca,  common  carotid. 


Jisc,  Isc,  right  and  left  subclavian  arteries. 
i?m,^m, right  and  left  innominatearteries. 
cut,  arteria  cuticularis. 
occ,  arteria  occipitalis. 

V  c,  vena  cardinal! s. 

V  c7,  right  vena  cava. 

V  s,  left  vena  cava. 

vi,  inferior  (posterior)  vena  cava. 

ces,  (esophageal  artery. 

wi,  mesenteric  artery. 

s,  spiracular  or  branchial  fissure. 

«,  nostril. 

dc,  ductus  cuvieri. 

I,  lingual  artery. 


ON  THE   ORIGIN  OF  GENERA.  (Ji 

natatoricB,  wliicli  is  the  homologue  of  the  A.  pulmonalis  of  air- 
breathers,  issues  in  Lepidosteus  from  the  last  vena  IrancMcdis, 
thus  receiving  aerated  blood  from  the  gills.  In  Lepidosiren  it 
issues  from  the  point  of  junction  of  two  gill-less  and  two  gill-bear- 
ing venoR  hrancMales,  thus  receiving  mixed  blue  and  red  blood,  or 
blue  blood  altogether,  Avhen  the  branchiae  are  not  in  functional 
activity.  In  Proteus  it  issues  from  the  last  vena  branchialis, 
where  it  receives  the  ductus  hotalli  of  the  preceding  vein,  which, 
when  the  gill  is  inactive,  becomes  a  gill-less  aorta-bow,  which  brings 
it  only  carbonized  blood,  which  it  readily  aerates  in  the  swim- 
bladder,  now  become  a  lung.  The  ventricle  is  homologous  with 
the  preceding.  In  salamanders,  where  the  substitution  of  the 
accessory  gill  arches  by  the  ductus  hotalli,  converts  the  arterice 
and  vencB  hrancMales  into  ^^  aorta-bows,"  the  A.  pulmonalis  is 
given  off  from  the  posterior  bow,  and  receives  henceforth  mixed 
blood.  In  the  Anura  the  origin  is  the  same,  but  nearer  the  heart. 
In  CaeciliidaB  it  approaches  the  heart  so  far  as  to  issue  from  the 
extremity  of  the  hulhus  arteriosus,  which  is  now  divided  by  an 
incomplete  septum,  one  half  conveying  blood  to  the  aorta-roots, 
and  the  other  to  the  A.  pulmonalis.  This  septum  was  already 
preceded  by  a  longitudinal  valve  with  free  margin  in  the  Anura  ! 
As  if  to  meet  the  coming  event,  a  trace  of  ventricular  septum  ap- 
pears at  the  apex  within.  There  can  now  be  no  question  of  the 
homology  of  the  ventricles  of  the  gar,  and  of  the  Cascilia.  But 
we  have  next  the  true  Eeptilia.  The  hulhus  arteriosus  is  split 
externally,  as  it  already  was  internally,  but  it  is  first  represented 
in  most  tortoises  by  an  adherent  portion,  one  half  being  the  now, 
to  this  point,  independent  arteria  pulmonalis  and  the  other  the 
nearly  sjjlit  aorta-roots.  There  can,  I  think,  be  little  question  of 
the  exactitude  of  the  homology  throughout. 

It  is  no  less  certain  that  the  salamander  *  fulfills  in  its  devel- 
opment the  different  stages  to  its  permanent  one,  and  is  identical 
in  each  stage,  in  respect  to  this  point,  with  the  orders  it  represents 
at  the  time.  This  is  true  even  of  the  long  period  during  which 
it  bears  the  long  branchial  appendages  and  contained  arteries  and 
veins  which  are  not  found  in  fishes  ;  it  is  then  like  the  Protop- 
terus,  which  has  hyoid  venous  arches  and  appendages  of  those 
arches  at  the  same  time.  The  tortoise  f  and  Troj^idonotus  I  are 
also  identical  in  their  successive  stages  with  the  types  already 

*  Amblystoma.  f  Agassiz.  X  Rathke. 


62  GENERAL  EVOLUTION". 

eniiinerated,  the  external  or  appendicular  branchial  vessels  being 
omitted,  as  belonging  to  the  special  serial  deyelopment  of  the  line 
of  air-breathing  Anallantoidans.  The  division  of  the  bulbus  arte- 
riosus into  three  instead  of  two  may  indicate  a  case  of  inexact 
parallelism  ;  but,  on  the  other  hand,  it  may  be  that  the  pulmonary 
partition  is  completed  a  little  before  the  aorta-root  partition,  thus 
passing  through  the  batrachian  permanent  type.  For  explana- 
tions of  inexactitude  see  under  Part  II.  No  doubt  the  batrachian 
type  of  hulhus  arteriosus  is  passed  by  many  serpents  less  extreme 
and  specialized  than  the  Tropidonotus. 

The  aortic  and  pulmonary  divisions  of  the  bulbus  in  the  Cae- 
cilia  are  not  laterally  placed,  but  one  is  dorsal  and  the  other  ven- 
tral, the  one  passing  a  little  spirally  to  the  right  of  the  other.  So 
the  pulmonary  division  of  the  bulbus  turns  over  to  the  right  in 
the  Anura.  When  the  septum  of  the  true  reptiles  appear,  it  rises 
on  the  anterior  wall  of  the  ventricle  till  it  is  seen,  in  Eunectes,  to 
meet  the  partition  between  the  arteria  pulmo7ialis  and  aorta-roots^ 
and  we  have  at  once  the  right  and  left  ventricles  of  the  bird  and 
mammal  structurally  and  functionally.  Thus  are  the  two  ven- 
tricles of  man  the  same  as  the  one  ventricle  of  the  fish,  merely 
divided  by  a  septum.* 

In  the  fissure  of  the  aortic  bulbus,  in  the  reptiles,  a  spiral  turn 
is  again  given,  and  in  Testudo  the  one  aorta-root  issues  behind 
the  other.  In  the  crocodile  the  turn  is  still  greater,  and  the 
right  aorta-root  issues  to  the  left  of  the  left  root,  and  vice  versa. 
In  the  birds  we  have  lost  the  left  root,  and  parallelism  ceases  with 
this  change.  In  the  Mammalia  the  right  root  turns  to  the  left, 
so  that  in  the  comparison  of  these  classes  the  rule  of  von  Baer 
above  quoted  is  true  ;  no  mammal  at  present  known  is  identical 
in  a  foetal  stage  with  any  fully  grown  bird,  but  with  a  foetus  of 
the  same,  up  to  a  certain  point.  But  for  both  classes  the  joaral- 
lelism  of  those  below  them  holds  true. 

But  it  is  with  the  exact  parallelism  or  identity  of  genera  that 
we  have  to  do  in  the  present  essay.  That  being  established,  the 
inexact  parallelism  between  the  modern  representatives  of  higher 
groups  follows  by  a  process  of  reduction. 

*  Agassiz,  I.  c  ,  denies  the  homology  of  the  ventricles  of  the  turtle  and  mammal; 
but  it  appears  to  me  erroneously.  He  says  :  "  The  fact  that  the  great  blood-vessels 
{aorta  and  art.  puhnonalis)  start  together  from  the  cavum  venosum  seems  to  prove 
that  the  two  cavities  in  the  heart  of  turtles,  which  are  by  no  means  very  marked, 
do  not  correspond  to  the  two  ventricles  in  Mammalia  and  birds." 


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ON  THE   ORIGIN"  OF  GENERA. 


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74  GENERAL  EVOLUTION. 

6.  TJie  Extent  of  Parallelism. 

Prof,  de  Serres  and  others  have  stated  it  as  their  belief  that 
the  lower  ^* branches"  of  the  animal  kingdom  are  identical  with 
the  undeveloped  forms  of  the  higher  ;  i.  e.,  that  the  mollusk  and 
articulate  are  not  merely  parallel  with,  but  the  same  as  the  lower 
conditions  of,  the  vertebrate.  The  works  of  various  embryologists, 
as  von  Baer  and  Lereboullet,  have  shown  this  statement  to  be 
erroneous,  *^and  founded  on  false  and  deceptive  appearances." 
The  embryos  of  the  four  great  branches  of  the  animal  kingdom 
appear  to  be  distinct  in  essential  characters  from  their  first 
appearance.  But  Lereboullet,  who,  in  his  prize  essay,  has 
compared  with  care  the  development  of  the  trout,  pike,  and 
perch  of  the  Teleosts,  with  that  of  a  Lacerta  among  reptiles,  has 
failed  to  point  out  characters  by  which  the  embryos  of  the  two 
vertebrate  classes  essentially  differ,  for  a  considerable  period.  It 
is  true  that,  as  each  and  all  of  the  species  belong  to  widely  differ- 
ent generic  series,  parallelism  is  of  the  kind  to  be  called  inexact 
or  remote.  But  enough  is  known  of  embryology  and  paleontol- 
ogy to  render  it  extremely  probable  that  the  historic  predecessors, 
of  the  types  whose  embryology  Lereboullet  studied,  formed  a  se- 
ries of  parallels  of  the  kind  termed  in  this  essay  exact. 

Lereboullet  states  that  a  certain  difference  exists  between  the 
eggs  of  the  fishes  and  those  of  the  Lacerta.  This  is  for  us  merely 
stating  that  the  parents  of  the  embryos  differ,  a  fact  which  no  one 
will  contest.  The  same  may  be  said  of  the  elevated  or  depressed 
character  of  the  surface  of  the  vitellus  on  which  the  embryo  re- 
poses. 

Secondly,  after  the  appearance  of  the  embryo  the  Lacerta  is 
furnished  with  the  amnios  and  allantois  ;  the  Teleost  not.  This 
is  certainly  neither  a  generic,  ordinal,  nor  class  character  of  the 
adult,  for  it  is  but  temporary  ;  therefore,  in  generic,  ordinal,  and 
class  characters  the  embryos  of  the  Teleost  and  Eeptile  are  still 
identical.  It  is  a  physiological  character,  and  not  morphological, 
and  therefore  far  the  less  likely  to  be  a  permanent  one,  even  in 
embryos,  under  changed  circumstances.  The  female  of  one  of 
the  species  of  Trachycephalus  inverts  the  skin  of  the  back  at  one 
season  of  the  year  to  receive  her  eggs,  because  she  can  not  lay 
them  in  the  water  ;  the  other  species  of  the  genus  do  not.  The 
next  genus  in  direct  morj)hological  line  possesses  a  single  species 
whose  female  does  the  same  for  the  same  reason  ;  but  the  rela- 


ON  THE  ORIGIN  OF   GENERA.  75 

tions  of  these  species  and  genera  are  zoologically  the  same  as 
though  this  modification  did  not  occur.  Many  such  instances  will 
occur  to  many  naturalists.  It  is  not  pretended  that  they  are  as 
important  as  the  presence  of  the  allantois  ;  but  they  constitute  a 
character,  no  doubt,  similar  in  kind,  and  entirely  at  the  service  of 
the  needs  of  the  great  system  of  morphological  succession.  The 
same  may  be  said  of  the  vascular  area  of  the  Reptile. 

Lereboullet  concludes  his  summary  of  the  differences  between 
the  Teleost  and  Reptile,  up  to  the  period  of  completion  of  the 
heart,  by  saying,  *^  It  is  easy  to  perceive  that  all  these  differences, 
however  imj)ortant  they  may  appear,  are  constituted  by  the  acces- 
sory organs  of  the  embryo,  and  do  not  modify  the  development  of 
the  latter,  which  progresses  in  reality  exactly  as  in  the  fishes." 
He  says  the  same  previously,  as  to  the  relation  of  the  same  to  the 
bird  and  mammal. 

We  have,  then,  in  the  embryos  of  the  lower  vertebrates  at  a 
certain  time  in  the  history  of  each,  an  ''exact  parallelism''^  or 
identity  with  the  embryonic  condition  of  the  type  which  pro- 
gresses to  the  next  degree  beyond  it,  and  of  all  the  other  types 
which  progress  successively  to  more  distant  extremes. 

We  have,  however,  so  far,  every  reason  to  suppose  that  the 
embryos  of  the  other  branches  of  animals  never  present  an  exact 
parallelism  with  those  of  the  Vertebrata.* 

The  embryo  of  the  fish  and  that  of  the  reptile  and  mammal 
may  be  said  to  be  generically,  if  not  specifically,  identical  up 
to  the  point  where  preparation  for  the  aerial  respiration  of  the 
latter  appears.  They  each  take  different  lines  at  this  point. 
The  fish  diverges  from  the  course  of  the  reptile,  and  proceeds 
to  a  different  goal ;  the  shark  does  the  same,  but  proceeds  a 
shorter  distance ;  while  the  Dermopter  scarcely  leaves  the  point 
of  departure.  No  doubt,  there  have  been  types  which  never 
left  this  point  and  tvliose  plan  of  circulatory  system  is  identical 
with  that  of  the  embryo  reptile  and  mammal.  Such  a  type  was 
only  generically  different  from  the  reptile  or  mammal  ivhich  had 
only  taken  the  succeeding  step,  provided  other  structures  were 
not  superadded. 

By  comparing  the  development  of  types  of  different  classes  in 

*  At  about  the  time  this  was  written  the  important  papers  of  Haeckel  on  his 
admirable  Gastraea  theory  were  published,  but  had  not  reached  the  author.  Haeckel 
shows  the  approximate  identity  of  all  the  types  of  embryonic  development.  (Note, 
1886.) 


76  GENERAL  EVOLUTION. 

certain  features  whicli  are  only  ordinal  or  generic  in  meaning,  yery 
erroneous  conclusions  may  be  reached  by  the  inexact  student  as 
to  the  want  of  parallelism  of  classes  to  each  other.  Thus  Rathke 
says  of  the  development  of  the  eye  of  the  snake  Tropidonotus,  at 
a  certain  period,  that  it  is  far  in  advance  of  that  of  the  mammal 
at  the  same  stage.  Here,  says  the  objector,  is  a  case  where  their 
parallelisms  do  not  coincide  ;  the  mammal  is  really  similar  to  a 
younger  stage  of  the  reptile. 

But,  in  fact,  the  size  of  the  eye  is  but  a  generic  or  family  char- 
acter ;  if  the  development  of  the  lemur  had  been  compared  with 
the  snake,  the  mammal  would  have  been  found  to  be  in  advance  ; 
of  the  mole,  much  farther  behind.  If  the  snake  selected  were  the 
purblind  Atractaspis,  almost  any  mammal  would  have  been  in 
advance  ;  if,  on  the  other  hand,  the  great-eyed  Dii3sas,  but  few 
Mammalia  would  have  been  parallel  to  it. 

In  a  word,  to  find  exact  parallelism  it  is  necessary  to  examine 
the  closest  allies. 

It  is  also  of  first  importance  to  distinguish  between  the  exist- 
ence of  generic  or  higher  characters,  and  their  condition  under 
various  circumstances  of  individual  life.  If  a  foetal  or  larval 
character  be  conserved  through  the  adult  life  of  a  type,  it  will  be 
of  course  adapted  to  the  functions  of  mature  age.  Thus  the  un- 
developed character  of  the  horns  of  the  genus  of  deer,  Rusa,  are 
not  accompanied  with  the  marks  of  individual  youth  of  the  cor- 
responding stage  of  Cervus ;  its  individuals  are  fully  grown  and 
functionally  perfect.  The  species  of  Hyla  are  not  small  and  in- 
capable of  self-preservation  and  reproduction,  as  is  the  corre- 
sponding stage  of  Trachycephalus  ;  they  are  functionally  devel- 
oped. The  student  need  not  be  surprised,  then,  if,  when  identity 
or  exact  parallelism  is  asserted,  he  finds  some  differences  depend- 
ent on  age  and  adaptation,  for  if  he  be  an  anatomist  he  need  not 
be  informed  that  a  morphological  relation  constitutes  types  what 
they  are,  not  a  physiological. 

II.    OF   KETARDATIOK   AI^D   ACCELEEATIOK   11^   GENERIC   CHAE- 

ACTEES. 

First.     Of  adult  metamorphosis : 

The  question  has  necessarily  arisen,  Have  these  remarkable 
relations  between  genera  resulted  from  an  arrangement  of  distinct 
generations  according  to  a  permanent  scale  of  harmony,  or  have 
the  same  genetic  series  of  individuals  been  made  to  assume  the 


ON  THE  ORIGIN   OF  GENERA.  77 

different  positions  at  tlie  same  or  different  periods  of  the  earth's 
history.* 

Prof.  Marcel  de  Serres  proposed  the  theory  of  repressions  of 
develojDment  to  account  for  the  existence  of  the  lower  groups  of 
animals  as  7iow  existing^  an  error  easily  exposed,  as  has  been  done 
by  Lereboullet  in  his  yarious  important  embryological  writings. 
But  little  obseryation  is  sufficient  to  prove  that  a  mammal  is  not 
a  shark  where  it  has  five  gill-arches  or  aorta-bows,  nor  a  batrachian 
where  it  has  three,  or  a  reptile  where  it  has  the  two  aorta-roots. 
This  has  been  already  sufficiently  pointed  out  by  von  Baer,  who 
says  there  is  "  keine  Eede  "  of  such  a  theory  as  was  afterward 
proposed  by  de  Serres.  Thus  are  true  the  rules  propounded  by 
this  author,  f  3.  ^^Each  embryo  of  a  given  animal  type,  instead 
of  passing  through  the  other  given  animal  found,  diverges  still 
more  from  it."  4.  ^^  In  the  basis,  therefore,  the  embryo  of  a 
higher  animal  type  is  never  identical  with  an  inferior  type,  but 
with  the  embryo  only  of  the  latter." 

I  think  that  I  have  already  made  some  progress  in  proving 
that  the  near  or  true  generic  relationship  is  one  of  absolute  devel- 
opmental repression  or  advance.  Paleontology  shows  that  fami- 
lies and  orders,  as  now  existing,  were  preceded  in  time  by  groups 
which  are  synthetic  or  comprehensive,  combining  the  common 
characters  of  modern  generic  series.  This  process  of  synthesis 
must,  it  is  obvious,  if  continued,  result  in  the  near  approximation 
of  the  single  representatives  of  the  now  numerous  and  diverse 
groups.  There  is  every  reason  to  believe  that  a  backward  view 
through  time  will  show  this  to  have  prevailed  throughout  the 

*  Some  naturalists  seem  to  imagine  that  the  demonstration  of  the  existence  of 
intermediate  types  is  only  necessary  to  establish  a  developmental  hypothesis.  Thus 
Dr.  Dohrn  ("  Ann.  Magaz.  N.  Hist.,"  1868),  writing  of  his  discovery  of  that  most 
interesting  genus,  Eugereon,  which  combines  characters  of  Neuroptera  with  those  of 
Hemiptera,  does  not  hesitate  to  say  that  it  proves  the  truth  of  Darwin's  theory. 
Now,  it  appears  to  me  that  a  demonstration  of  the  existence  of  a  regularly  graduated 
succession  of  types,  from  the  monad  to  man,  would  be  only  the  minor  of  a  syllogism 
without  its  major,  in  evidence  for  development,  so  long  as  the  proof  of  transition 
of  one  step  into  another  is  wanting ;  and  the  idea  that  such  a  discovery  could  estab- 
lish a  developmental  theory  is  entirely  unfounded.  Indeed,  the  reasoning  in  which 
some  indulge— if  we  dare  so  call  the  spurious  article— based  on  this  premise  alone, 
is  unworthy  of  science.  The  successional  relation  of  types,  though  a  most  important 
element  in  our  argument,  has  been  long  known  to  many  who  give  no  sanction  to 
the  idea  of  development. 

f  "  Entwickclungsgeschichte,"  p.  224. 


78  GENERAL  EVOLUTION. 

Vertebrata  and  other  brandies,  as  we  already  can  in  part  prove. 
And  I  have  no  doubt  that  the  synthetic  types,  which  represent 
modern  orders,  have  existed  in  a  generic  relationship  subordinate 
to  the  plan  of  the  synthetic  class,  and  that  the  latter  have  existed 
as  genera  only,  of  the  type  of  the  great  branch.  This  is  not  ideal. 
We  only  have  to  look  to  our  extinct  ganoids^  Archegosaurs,  Laby- 
rinthodonts,  Compsognathus,  Archseopteryx,  Ornithorhynchus, 
etc.,  to  realize  these  facts. 

The  first  genera  then  formed  a  scale  of  which  tlie  members 
were  identical  with  the  undeveloped  stages  of  the  highest,  and 
each  to  each  according  to  their  position. 

Such  a  series  of  antitypic  groups  having  been  thus  established, 
our  present  knowledge  will  only  permit  us  to  suppose  that  the 
resulting  and  now  existing  kingdoms  and  classes  of  animals  and 
plants  were  conceived  by  the  Creator  according  to  a  plan  of  his  own, 
according  to  his  pleasure.  That  directions  or  lines  of  development 
toward  these  ends  were  ordained,  and  certain  laws  applied  for  their 
realization.  That  these  laws  are  the  before-mentioned  law  of  re- 
tardation AND  ACCELERATION  ;   and  law  of  NATURAL  SELECTION. 

The  first  consists  in  a  continual  crowding  backward  of  the 
successive  steps  of  individual  development,  so  that  the  j^eriod  of 
reproduction,  while  occurring  periodically  with  the  change  of  the 
year,  falls  later  and  later  in  the  life  history  of  the  species,  confer- 
ring upon  its  offspring  features  in  advance  of  those  possessed  by 
its  predecessors,  in  the  line  already  laid  down  partly  by  a  prior 
suppression  on  a  higher  platform,  and  partl}^,  as  above  supposed, 
by  the  special  creative  plan.  This  progressive  crowding  back  of 
stages  is  not,  however,  supposed  to  have  progressed  regularly.  On 
the  contrary,  in  the  development  of  all  animals  there  are  well- 
known  periods  when  the  most  important  transitions  are  accom- 
plished in  an  incredibly  short  space  of  time  (as  the  passage  of 
man  through  the  stages  of  the  aorta-bows,  and  the  production  of 
limbs  in  Batrachia  anura)  ;  while  other  transitions  occupy  long 
periods,  and  apparently  little  progress  is  made. 

The  rapid  change  is  called  metamorphosis  ;  the  intervening 
stages  may  be  called  larval  or  pupal.  The  most  familiar  examples 
are  those  which  come  latest  in  life,  and  hence  are  most  easily  ob- 
served, as  in  the  insects  and  frogs.  "When,  during  the  substationary 
period,  the  species  reproduces,  a  constancy  of  type  is  the  result ; 
when  the  metamorphosis  only  appears  at  the  period  of  reproduc- 
tion, a  protean  type  is  the  result ;  when  the  metamorphosis  is  crowd- 


ox  THE   ORIGIN   OF   GENERA.  79 

ed  back  to  an  earlier  period  of  life,  then  we  have  another  persistent 
type,  but  a  new  genus  of  a  higher  grade  than  its  predecessor. 

In  reviewing  many  examples  everywhere  coming  under  the  eye 
of  the  naturalist,  it  is  easy  to  perceive  what  would  constitute  a 
plastic  and  what  a  conserved  condition  of  generic,  or  even  of  spe- 
cific form. 

As  one  or  more  periods  in  the  life  of  every  species  is  character- 
ized by  a  greater  rapidity  of  development  (or  metamorphosis)  than 
the  remainder,  so  in  j^roportion  to  the  approximation  of  such  a 
period  to  the  epoch  of  maturity  or  reproduction,  is  the  offspring 
liable  to  variation.  During  the  periods  corresponding  to  those  be- 
tween the  rapid  metamorphoses  the  characters  of  the  genus  would 
be  preserved  unaltered,  though  the  period  of  change  would  be 
ever  approaching. 

Hence  the  transformation  of  genera  may  have  been  rapid  and 
abrupt,  and  the  intervening  periods  of  persistency  very  long  ;  for 
it  is  ever  true  that  the  macrocosm  is  a  parallel  or  repetition  of  the 
microcosm  in  matter  and  mind.  As  the  develoj^ment  of  the  in- 
dividual, so  the  development  of  the  genus.  We  may  add  :  so  the 
development  of  the  whole  of  organized  beings. 

These  metamorphoses  may  be  fitly  compared  to  those  in  the 
molecular  constitution  of  matter.  The  force  of  cohesion  between 
the  atoms  of  a  vapor  steadily  increases  with  descending  tempera- 
ture, and  in  a  regular  ratio,  till  a  given  point  is  reached,  when  a 
sudden  metamorphosis  to  a  denser  or  liquid  condition  takes  place. 
Nor  have  we  reason  to  believe,  with  regard  to  many  substances, 
that  there  is  any  parallel  relation  between  the  temperature  and  the 
molecular  constitution  before  or  after  the  metamorphosis  takes 
place.  So,  the  temperature  continuing  to  descend,  the  molecular 
character  of  the  liquid  remains  unchanged  until,  the  vis  conserva- 
trix  suddenly  giving  way  at  the  ordained  point,  a  soild  is  the  re- 
sult. Thus,  while  the  change  is  really  progressing,  the  external 
features  remain  unchanged  at  other  than  those  points,  which  may 
be  called  expression-points. 

Now,  the  expression-point  of  a  new  generic  type  is  reached 
when  its  appearance  in  the  adult  falls  so  far  prior  to  the  period  of 
reproduction  as  to  transmit  it  to  the  offspring  and  to  their  de- 
scendants, until  another  expression-point  of  progress  be  reached. 

Thus  a  developmental  succession  does  not  so  obliterate  the  lines 
drawn  around  Nature's  types  as  to  render  our  system  ineffectual 
as  an  exDression  of  them. 


80 


GENERAL  EVOLUTION. 


The  successional  acceleration  or  retardation  in  metamorphosis 
may  be  best  illustrated  in  certain  tailless  batrachians,  by  the  fol- 
lowing tables.  These  are  taken,  it  will  be  remembered,  from  the 
Bufonidse  and  Hylidse  as  examples  of  '^  exact  parallelism  " ;  three 
are  now  added  from  the  Eanidae  and  Discoglossidae.  The  case  of 
^'  inexact  parallelism  "  is  that  of  the  Scaphiopodidae. 

Whether  they  are  cases  of  acceleration  or  retardation  can  only 
be  determined  by  reference  to  the  paleontology  of  the  respective 
groups,  or  a  careful  comparison  of  times  of  metamorphosis.  In 
the  case  of  the  Discoglossidae  I  suspect  it  to  be  retardation,  as  the 
highest  genus  is  extinct.  The  others  I  shall  arrange  with  them 
for  temporary  conyenieuce.  Were  I  dealing  with  a  group  of  Ga- 
noids, I  should  imagine  the  process  to  be  retardation,  as  this 
group  is  going  out  of  existence.  On  the  other  hand,  were  they 
higher  Oscine  birds,  we  might  imagine  the  case  to  be  reversed. 


Assumed, 
140th  gen. 
120th  gen. 
100th  gen. 

80th  gen. 

60th  gen. 

40th  gen. 

20th  gen. 
1st  gen. 


Series  No.  1.    No.  2. 

Bombinator. .  .Hyla 

Alytes  * 

No.  3. 

.Epidalea. 

e  : 

Discoglossus 

Scy  topis 

e    Pf      :    F 

e    Pf 

F       : 

. .  Buf  o  sp. 

Osteocephalus. . . 

e.  Pf  F 

Ex    : 

.  ,Bufo  sp. 

Pf  :  F 

Ex     t 

Latonia Trachycephalus. 

Pf 

?F      :      Ex 

t 

.  .Peltaphryne  . 

?  :                            : 

p  >-s  5  c>  rj  «i  2 

«  >-^  3  g.  O  .°°  g" 
P'  £S   r^  —  CO  H 


3  t:- 

CO  a 
of 


o 

O  ffi  „ 

P-S.S 

IX    ^ 

■    ^ 


o 

CO 

o 

W 


s 

o 
■-1 

SS 

-I 

o 
o 


O    CO 

►c  P 
•s  "*• 
C  3- 
P- 
3 
o 
o 


Fig.  3. 


T 

T 

T    F 

T    F  Ex 

T        F    Ex 

o 


^ 

f 

<1         ^ 

"-J 

O 

<r+  o  r"2 

o 

CD 

(^  B  g  :5 

ft    3    CD    o 

f1 

rt> 

rt- 

t-t-  c  "■» 

o 

P 

t='2.'C  2; 

00 

•     3  3-0 

OD 

ft  P  3 

Pi 


ft  y< 

P  00 

p  22. 

Q  CD 


p  o 


orq 


ft 

1-1 

o 
& 

3 
ft 
ft 


Ixalus. 


i 


Rhacophorus, 


Polypedates. 


No  vera,  teeth. 
Sometimes  " 
Always       " 


^  2 
§1 

P 


ft 


Points  not  attained. 
Fig.  4. 


*  A  parotoid  gland  of  small  size  is  added  here,  but  is  not  generic  as  compared  with  Bom- 
binator, as  the  latter  has  collections  of  crypts  on  the  same  region  and  over  the  body. 


ON  THE   ORIGIN   OF  GENERA. 


81 


u 


a  OB 

%  0 

Pi 
O 


OS 


EC 


be 


o 


CD 

a, 


/ 

* 

* 

/ 

/ 

u 
* 

1 

Death. 


Eeprodiic- 
tion. 


Tail  lost  (re- 
tard.). 

Temp,  roof 
(ace). 

Ossif.  front 
(ace). 


Hatching. 


6 

M 

PR 


\ 


\ 


\ 


\ 


Reproduce. 
Prefrontals  unit. 

Ethmoid  oss. 
Tail  lost. 

Frontak  0B8i£ 


p. 

o 

e 


a 


Hatched. 


In  the  preceding  diagrams  each  horizontal  cohimn  represents 
the  life  history  of  the  individuals  of  each  genus.  The  line  of 
dots,  stars,  etc.,  represents  the  same  developmental  stage  of  each, 
as  it  appears  earlier  or  later  in  the  life  of  the  individuals.  The 
point  of  crossing  the  breeding  period  is  that  at  which  the  charac- 
ter is  rendered  permanent.  When  the  change  falls  on  this  period 
the  character  is  not  generic,  as  in  Ixalus,  Fig.  4.  The  period  of 
losing  the  tail,  like  that  of  breeding,  is  represented  as  occurring  at 
nearly  the  same  time  in  the  history  of  every  genus,  as  it  is  gener- 
6 


82  GENERAL  EVOLUTIOK 

ally  seasonal.  Yet  this  is  not  always  so,  and,  like  the  other  char- 
acters, has  most  likely  had  its  period  of  shifting.  Compare  differ- 
ence of  time  of  development,  for  instance,  of  the  frontal  and  pre- 
frontal bones  in  Figs.  3  and  6.  The  comparison  of  the  adult 
stages  of  the  less  developed  genera,  at  the  tops  of  the  columns, 
with  the  larval  conditions  of  those  more  fully  developed,  may  be 
traced  in  the  absence  of  characters  which  appear  in  the  latter.  I 
have  convinced  myself  of  the  accuracy  of  the  above  relations  by 
the  examination  of  many  skeletons  and  wet  preparations  of  adults 
and  larvae. 

The  diagrams*  are  representations  of  nature,  and  not  ideal 
sketches.  It  is  to  be  noted  as  remarkable  that  the  advance 
throughout  so  many  diverse  groups  is  in  the  same  direction,  viz., 
to  complete  or  excessive  ossification  of  the  cranium  ;  and  this 
identity  of  progress  might  be  readily  shown  hy  adding  other  char- 
acters, were  it  not  that  the  tables  would  become  too  complex  for 
convenience. 

Has,  any, such  transition  from  genus  to  genus  ever  heen  seen  to 
occur  9 

It  must  of  course  take  place  during  the  life  of  the  individuals 
of  a  species,  and  probably  at  different  times  during  the  lives  of 
different  individuals,  dependent  on  their  relative  vigor.  In  our 
view,  ordinary  metamorphosis  is  such  a  change,  and  we  have 
stated  its  bearing  in  this  form,  that  ^'  every  character  distinguish- 
ing suborders,  families,  and  genera  is  to  be  found  among  the  indi- 
viduals of  some  species,  living  or  extinct,  to  mark  new  varieties 
or  stages  of  growth." 

a.   The  Developmental  Relation  of  Generic  to  Specific  Characters. 

For  the  relation  of  the  law  of  retardation  and  acceleration  to 
specific  characters  we  will  look  to  development  again.     While  the 

*  Notes  on  the  diagrams :  Fig.  4.  Polypedates  is  here  restricted  to  P.  maeulatus 
and  P.  quadrilineatus.  The  other  species  are  referred  to  Rhacophorus,  which  has 
not  hitherto  rested  on  any  proper  basis ;  the  asserted  character — the  palmation  of 
the  hands  —  being  one  quite  graduated  from  species  to  species  among  Hylas. 
Chiromantis,  Peters,  is  referred  to  the  same,  as  its  character  is  not  strongly 
marked  and  is  visible  in  other  species.  For  similar  reasons  Lcptomantis  is  referred 
to  Ixalus. 

Fig.  6.  In  each  of  series  ii  and  iii,  two  series  are  mingled  for  the  sake  of  com- 
paring the  structures  of  the  prefontal  bones.  Thus  Heteroglossa,  Staurois,  Hylo- 
rana  and  Trypheropsis  are  one  series,  and  Hyperolius  and  Hylambates  members  of 
another. 


ON  THE   ORIGIN   OF  GENERA.  §3 

young  of  Trachycephalus  are  successively  different  genera,  they 
preserve  most  of  their  specifle  characters  so  as  not  to  be  mistaken. 
Agassiz  says  of  the  development  of  the  North  American  turtles,* 
"  I  do  not  know  a  turtle  which  does  not  exhibit  marked  specific 
peculiarities  long  before  its  generic  characters  are  fully  devel- 
oped." The  same  thing  can  be  said  of  the  characters  of  our  sala- 
manders, whose  specific  marks  appear  before  their  generic  or  even 
family  characters.  I  suspect  that  this  will  be  found  to  be  a  uni- 
versal law. 

It  also  follows,  if  a  developmental  process,  as  proposed,  has 
existed,  that  at  times  the  change  of  generic  type  has  tahen  place 
more  rapidly  than  that  of  specific,]  and  that  one  and  the  same 
species  {if  origin  he  the  definition)  has,  in  the  natural  succession, 
existed  in  more  than  one  genus. 

Apart  from  any  question  of  origin,  so  soon  as  a  species  should 
assume  a  new  generic  character  it  ceases,  of  course,  to  be  specific- 
ally the  same  as  other  individuals  which  have  not  assumed  it.  If 
supposed  distinctness  of  origin  be,  however,  a  test  of  specific 
difference,  we  shall  then  have  to  contend  with  the  paradox  of  the 
same  species  belonging  to  two  different  genera  at  one  and  the 
same  time. 

It  follows,  therefore,  in  our  interpretation  of  nature,  that 
groups  defined  by  coloration  alone  are  not  to  be  regarded  as  genera, 
as  is  done  by  some  ornithologists  and  entomologists.  They  are 
simply  groups  of  species  in  which  distinctive  generic  characters 
had  not  appeared  up  to  the  period  of  reproduction.  Inasmuch 
as  in  development  certain  specific  characters  appear  first,  among 
them  part  or  all  of  the  coloration  pattern,  it  is  obvious  that  the 
latter  do  not  belong  to  the  generic  category.  The  employment  of 
such  characters,  then,  in  this  sense,  is  only  to  commence  reversing 
the  terms  generic  and  specific,  and  to  inaugurate  the  process  of 
regarding  each  species  as  type  of  a  separate  genus. 

p.    Of  ProbaUe  Cases  of  Transition. 

Thus  the  transition  between  the  toothed  and  edentulous  con- 
ditions in  Cetacea  takes  place  in  the  ordinary  growth  of  the  indi- 
viduals of  the  genus  Globiocephalus,  and  the  transition  between 


*  Gontrib.  "  N.  Hist.  United  States,"  i,  p.  391.     Note. 

f  See  "  Proceedings  Academy,"  Philadelphia,  1867,  p.  86,  where  I  observe  that 
genei'ic  characters  are  probably  less  inherent  than  specific. 


84  GENERAL  EVOLUTION. 

the  ossified  and  non-ossified  types  of  Chelonia  occurs  during  the 
life  of  the  individuals  of  the  genus  Dermatemys. 

But,  in  attempting  to  demonstrate  this  proposition,  we  must 
bring  forward  facts  of  another  kind.  The  anti-developmentalists 
are  accustomed  to  put  such  changes  aside,  as  part  of  the  necessary 
history  of  established  types  ;  hence  we  will  not  aj^peal  to  such. 

1.  The  frog  Ranula  qffinis,  of  South  America,  was  described 
by  Peters  as  probably  a  climatal  variety  of  European  Bana  te7npo- 
raria.  In  this  he  is  supported  by  the  fact  that  the  specific  char- 
acters do  not  differ  more  than  would  characterize  it  as  a  local 
variety,  were  it  an  inhabitant  of  Europe.  But  I  have  found  that 
it  differs  generically  in  the  non-ossification  of  the  ethmoid  bone, 
as  has  been  confirmed  by  Steindachner,  and  represents  an  embry- 
onic condition  of  the  same  bone  in  Eana.  It  is  in  fact  an  unde- 
veloped Eana.  That  this  is  a  true  genus  is  confirmed  by  many 
specimens,  by  additional  species,  and  by  the  fact  that  the  allied 
genus  Trypheropsis,  embracing  three  species  in  the  same  region, 
differs  in  the  same  way  from  the  otherwise  identical  genus  of  the 
Old  World,  Hylorana. 

2.  The  South  African  Saurians,  ChamcBsaura  anguina  and 
Ma7icus  macrolepis,  are  very  closely  allied  in  specific  characters  in 
all  respects,  though  distinct.  They  have  one  important  ground 
of  generic  distinction  :  the  latter  has  one  pair  of  limbs  less  than 
the  former.  They  are  rudimental  in  Oham£esaura,  and  tlie  disap- 
pearance in  Mancus  is  but  another  step  in  the  same  direction. 
The  difference  in  specific  characters  is  of  mucli  less  degree. 

3.  In  the  genus  Oelestus  there  are  numerous  species,  which 
range  from  a  slender  snake-like  form  with  weak  limbs,  to  stouter, 
strong-limbed  forms  with  a  more  saurian  build.  Among  these 
the  Haytian  O.  plioxinus  is  well  distinguished  by  form  and  color- 
ation. An  allied  genus  from  the  same  region  is  Panolopus,  which 
in  specific  characters  approaches  the  C.  plioxinus  very  closely, 
much  more  so  than  any  Oelestus  (one  species  possibly  excepted). 
But  in  generic  characters  it  is  distinguished  by  the  loss  of  all  its 
toes  and  the  non-separation  of  nine  plates  on  the  end  of  the  muz- 
zle. The  genus  Diploglossus,  on  the  other  hand,  occupying  a 
superior  place  on  account  of  the  division  of  the  fronto-nasal  into 
three,  is,  in  specific  characters  (of  B.  7no7iotropis)  much  closer  to 
the  stout  Celesti  than  the  species  of  the  latter  genus  are  among 
themselves. 

4.  The  Gronim  nigrilahris  is  a  Silurid,  which  in  specific  char- 


OJT  THE   ORIGIN    OF   GENERA.  §5 

acters  more  nearly  resembles  the  Amiurus  lynx,  than  the  latter 
does  the  A.  albidus  and  many  other  species  of  the  genus.  The 
A.  lynx  is  found  in  the  same  streams.  The  important  generic 
character,  the  absence  of  eyes,  is,  however,  its  constant  feature 
(in  three  specimens  known  to  naturalists,  others  to  fishermen). 

5.  The  Cinclidium  maximum,  a  large  tree-toad  of  Brazil,  re- 
sembles in  all  its  characters  the  Gentrotelma  geograpMcum.  The 
specific  differences  between  them  amount  to  almost  nothing,  but 
both  sexes  of  the  former  grow  larger  and  are  furnished  with  a 
generic  peculiarity  in  the  addition  of  some  phalanges  to  the 
thumb. 

6.  The  Oporornis  agilis,  Baird,  a  North  American  bird  of  the 
Tanager  family,  resembles  very  closely,  in  form,  color,  and  habits, 
the  adjacent  species  of  the  adjacent  genus  Geothlypis.  While  its 
specific  characters  are  thus  very  close  to  Geothlypis  teplirocotis, 
it  differs  in  the  generic  feature  of  a  longer  wing.  By  this  it  is 
associated,  and  properly  so,  with  another  species  0.  formosus, 
which  has  the  general  color  and  habits  of  species  of  Myiodioctes 
(if.  canadensis),  the  next  related  genus. 

7.  The  following  fact  I  give  on  the  authority  of  Prof.  Leicly, 
who  will  publish  it  in  his  forthcoming  work  on  the  extinct  Mam- 
malia of  Nebraska,  etc. 

Three  species  of  Oreodon  occur  in  the  Miocene  strata ;  they 
are  a  larger,  a  medium,  and  a  small  sized  species.  In  the  Plio- 
cene beds  above  them  they  are  represented  by  three  species  of 
Merychyus,  which  are  in  all  respects  known,  identical  specific- 
ally with  the  three  preceding.  Each  one  may  thus  be  said  to  be 
more  nearly  allied  to  the  species  of  the  other  genus  than  to  its 
fellow  of  the  same  genus,  in  specific  characters.  But  each,  on  the 
other  hand,  differs  from  each  in  generic  characters.  The  teeth  of 
Merychyus  are  more  prismatic,  have  longer  crowns  and  shorter 
roots,  approaching  the  sheep,  as  Oreodon  does  the  deer.* 


*  This  phenomenon  suggests  an  explanation  on  the  score  of  adaptation,  which  the 
other  cases  do  not.  The  existence  during  the  later  period  of  a  tougher  material  of 
diet  would  increase  the  rapidity  of  wearing  of  the  crown  of  the  tooth,  and  require 
a  longer  crown  and  greater  rapidity  of  protrusion.  This  necessitates  a  dimi- 
nution of  the  basal  shoulder  and  shortening  of  the  roots,  producing  the  prismatic 
form  aforesaid.  The  deer  browse  on  forest  foliage,  which  is  more  tender,  while 
the  Cavicornia  graze  the  grasses,  which  contain,  as  is  known,  a  greater  amount  of 
silex  ;  hence  the  more  rapid  attrition  of  the  tooth. 

This  may  have  been  the  case  with  the  two  extinct  genera  ;  the  different  periods 


QQ  GENERAL  EVOLUTION. 

8.  The  Coreopsis  discoidea  T.  and  (r.,  var.  anomala,  Gray,  is, 
according  to  Mr.  Aubrey  Smith,  much  more  nearly  allied  to  Bid- 
ens  fro7idosa  than  to  other  species  of  its  own  genus,  and  the  latter 
is  nearer  to  it  than  to  other  species  of  Bidens.  It  differs  chiefly, 
if  not  altogether,  in  the  generic  character  :  the  barbs  of  the  ache- 
nia  are  directed  upward  ;  those  of  the  Bidens  downward. 

From  these  and  many  other  such  instances  it  may  be  derived  : 
That  the  nearest  species  of  adjacent  genera  are  more  nearly  allied 
in  specific  characters  than  the  most  diverse  species  of  the  same 
genus. 

9.  While  Taxodium  distichum  and  Glyptostrolus  europcens, 
conifers  of  North  America  and  of  Eastern  Asia,  respectively,  are 
readily  distinguished  by  generic  peculiarities  of  their  cones,  in 
specific  characters  they  appear  to  be  identical.* 

Confirmatory  of  this  proposition  is  the  statement  of  Parker  :  f 
*^In  tracing  out  the  almost  infinite  varieties  of  the  modifications 
of  any  one  specific  type  of  shelled  Rhizojood,  my  friend  Prof. 
Rupert  Jones  and  I  found  that  like  varieties  of  distinct  species  are 
much  nearer  in  shape  and  appearance  than  unlike  varieties  of  the 
same  essential  species."  (It  is  not  unlikely  that  species  should 
here  be  read  genus  and  variety  species,  though  the  latter  may  not 
fulfill  the  requirements  in  regard  to  distinctiveness  observed 
among  higher  animals.  In  types  like  the  Rhizopod,  forms  of  this 
grade  may  not  be  really  differentiated.  Their  enormous  geo- 
graphical range  would  suggest  this,  if  nothing  else. ) 

Objection. — A  class  of  objectors  to  the  preceding  explanation 
of  the  relations  in  question  will  ascribe  them  to  hybridization. 
They  have  already  done  so  to  considerable  extent  among  the 
Teleosts  (see  the  writings  of  von  Siebold,  Steindachner,  and 
Giinther).  That  hybrids  exist  in  nature  will  be  denied  by  none, 
but  that  they  are  usual  or  abundant  is  not  a  probable  condition  of 
a  creation  regulated  by  such  order  as  ours  is.  The  tendency  to 
modify  in  given  lines  of  generic  series,  if  admitted,  will  account 
for  many  of  the  cases  regarded  as  hybrids  by  the  above  authors, 
for  it  is  to  be  remarked  in  many  cases  how  the  generic  characters 

during  which  they  lived  may  have  seen  a  change  from  forest  to  praii'ie.  (It  is  not 
intended  to  suggest  that  the  species  of  the  two  genera  arc  necessarily  of  the  same 
or  any  given  number.) 

*  See  Meehan,  "  Proc.  Amer.  Ass.  Adv.  Sci.,"  1868.  Newberry,  "  Ann.  Lye," 
N.  Y.,  1868. 

f  "  Transac.  Zool.  Soc.,''  London,  1864,  p.  151. 


ON  THE   ORIGIN  OF  GENERA.  37 

are  strikingly  affected,  and  are  chiefly  used  in  guessing  at  tlie 
parentage.  This  is  among  Cyprinidae  so  much  the  case  that  there 
is  scarcely  an  example  of  a  hybrid  between  two  species  of  the  same 
genus  brought  forward,  but  often  between  species  of  different 
genera. 

y.  Ascertained  Cases  of  Transition. 

This  naturally  suggests  that,  in  accordance  with  the  theory  of 
acceleration  and  retardation,  a  transition  can  take  place  in  the 
life  history  of  species.  Have  we  any  means  of  proving  this  sus- 
picion ? 

1.  The  genus  Ameiva  (Saurians  of  South  America)  has  been 
composed  of  species  of  moderate  size  furnished  with  acutely  tri- 
cuspid teeth.  Teius,  on  the  other  hand,  embraces  very  large  spe- 
cies with  the  molars  obtusely  rounded  and  of  the  grinding  type. 
These  genera  are  generally  held  to  be  well  founded  at  present.  I 
find,  however,  that  in  Ameiva  pleii,  which  is  the  largest  species  of 
the  genus,  in  adults  the  greater  part  of  the  maxillary  and  mandib- 
ular teeth  lose  their  cusps,  become  rounded,  then  obtuse,  and 
finally  like  those  of  Teius.  While  young,  they  are  true  AmeivaB. 
Strangely  enough  the  A.  pleii,  from  Porto  Rico,  acquires  but 
three  such  obtuse  teeth  when  of  the  size  of  the  other  (St.  Croix) 
forms.  In  youth  the  teeth  of  all  are  as  in  other  Ameivse.  Here  is 
a  case  of  transition  from  one  genus  to  another  in  the  same  species. 

2.  In  the  important  characters  of  the  possession  of  branchiae, 
of  maxillary  bones,  and  of  ossified  vertebrae,  the  tailed  Batrachia 
presents  a  series  of  a  rising  scale,  measured  by  their  successively 
earlier  assumption.  Thus  Salamandra  atra^  produces  living 
young,  w^hich  have  already  lost  the  branchiae  ;  S.  maculosa  living 
young  with  branchiae  ;  Plethodon  f  produces  young  from  eggs 
which  bear  branchiae  but  a  short  time,  and  do  not  use  them  func- 
tionally ;  Desmogantlms  nigra  uses  them  during  a  very  short 
aquatic  life  ;  D,  fusca  and  other  Salamanders  maintain  them 
longer ;  while  Spelerpes  preserves  them  till  full  length  is  nearly 
reached.  Finally,  species  of  Amblystoma  reproduce  while  carry- 
ing branchiae,  thus  transmitting  this  feature  to  their  young  as  an 
adult  character.  And  it  is  a  very  significant  fact  that  Spelerpes, 
which  bears  branchiae  longest,  next  to  Amblystoma,  is  associated 


*  See  Scbreiber's  "  Isis,"  1833,  p.  527;  Koeliker,  "Zeitschr.  f.  wissensch.  Zoolo- 
gie,"  ix,  p.  464. 

f  Baird,  "  Iconographic  Encyclopaedia  "  ;  Wyman,  Cope. 


88  GENERAL  EVOLUTION. 

in  the  same  zoological  region  with  a  genus  (N'ecturus)  which  dif- 
fers from  its  four-toed  form  (Batrachoseps*)  in  nothing  more 
than  the  possession  of  the  osseous  and  branchial  characters  of  its 
larva,  in  a  permanent  and  rej^roducing  condition.  That  this  is  a 
genus,  to  be  one  day  converted  into  Batrachoseps  by  an  accelera- 
tion of  its  metamorphosis,  or  that  has  been  derived  from  it  by  the 
reverse  process,  I  am  much  inclined  to  believe,  f  In  supj^ort  of 
this  I  quote  the  following  examination  into  the  time  of  change  of 
the  species  of  Amblystoma  from  my  essay  on  that  genus  :  J 

*^  The  great  difference  between  the  different  species,  and  be- 
tween individual  species  in  this  respect,  may  be  illustrated  by  the 
following  comparison  between  the  size  of  the  animals  at  the  time 
of  losing  the  branchiae,  so  far  as  known,  and  that  to  which  they 
ultimately  attain. 

Species.  Size  at  loss  of  branchi^. 

In.  Lines. 

A.  jeffersonianum,  1  S'YS 

A.  punctatum,  1  10 

A.  conspersum,  1  10"5 

A.  opacum,  2  2 

A.  texense,  2  1 

A.  microstomum,  2  3'5 

A.  talpoideum,  3  (perhaps  too  large). 

A.  paroticum,  3  7*5  (not  smallest). 

....  {  S  1  to 

A.  tigrinum,  j  ^  ^ 

A  ^'  i  3  9-5  to  8  9 

A.  mavortium,  ■]  s  0 

A.  mexicanum,  ?  branchias  persistent.  8  " 

The  last  species,  though  not  uncommon  in  collections,  is  not 
known  to  pass  through  its  metamorphoses  in  its  native  country, 
but  reproduces  as  a  larva,  and  is  therefore  tj^DC  of  the  genus  Sire- 
don  of  Wagler,  Cuvier,  Owen,  and  others.  The  larva  of  A.  ?na- 
vortium  in  like  manner  reproduces,  but  their  offspring  have  in 
the  Jardin  des  Plantes  and  at  Yale  College  undergone  an  early 
metamorphosis.* 


ERAG] 

E  FULL  SIZE. 

In. 

Lines. 

6 

6-1 

6 

2 

7-5 

3 

9-5 

9 

4 

3 

9-5 

7-2 

2-5 

8  to  10 

*  See  Cope,  *'  Jour.  Ac.  Nat.  Sci.,"  Phila.,  1866. 

f  Necturus  differs  from  all  true  Salamanders  in  the  possession  of  the  os  interca- 
lare  of  the  skull;  the  parallelism  is  therefore  inexact.     (Note,  1886.) 
X  "  Proceed.  Academy,"  Phila.,  1867. 

*  Through  the  kindness  of  Prof.  Dumeril  I  have  received  both  larvae  and 
adult  of  the  species  here  noted,  and  observed  by  him.  The  larva  is,  as  he  states, 
Siredon  lichenoides  of  Baird,  while  the  adult  is  his  Amhlyntoma  mavortium^  not  A. 
tigriyium  {  =  luridum),  as  also  supposed  by  Dumeril.  (Note,  1886.  I  now  believe 
these  forms  to  belong  to  one  species.) 


.   ON  THE   ORIGIN   OF  GENERA.  §9 

Here  is  a  case  where  all  the  species  but  two  change  their 
generic  characters  ;  one  changes  them  or  not,  according  to  cir- 
cnmstances,  and  one  does  not  change  them  at  all.  What  are  the 
probabilities  respecting  the  change  in  the  first  set  of  species  ? 

As  we  know  from  the  experiments  of  Hogg,  Dumeril,  and 
others  that  metamorphosis  is  greatly  hastened  or  delayed  by  the 
conditions  of  temperature  and  light,  what  would  not  be  the  effect 
on  such  a  protean  species  of  a  change  of  topographical  situation, 
such  as  the  elevation  or  depression  of  the  land  ?  And  I  liaye  no 
hesitation  in  saying  that  if  the  peculiarities  of  series  of  individuals 
of  A.  tigrinum  and  A.  mavortmm,  in  the  respects  above  enumer- 
ated, were  permanent,  they  would  characterize  those  series  as  spe- 
cies, as  completely  as  any  that  zoologists  are  accustomed  to  recog- 
nize. For  the  evidences  on  this  head,  see  the  discussions  of  those 
species  in  my  monograph. 

The  experimxcnts  of  Hogg,  above  alluded  to,  are  as  follows,  as 
given  by  him  in  the  "Annals  and  Magazine  of  Natural  History." 

He  placed  a  number  of  impregnated  ova  of  frogs  in  vessels 
arranged  at  regular  distances  from  the  light,  in  a  cave.  The  les- 
sening degrees  of  light  were  of  course  accompanied  by  a  corre- 
sponding but  much  less  rapid  decline  in  temperature.  The  result- 
ing effects  on  the  metamorphosis  may  be  tabulated  as  follows  : 


310. 

day. 

60° 

56° 

53° 

51° 

3 

11 

Ecrg. 

Egg. 

Egg. 

20 

Larva  free, 

* 

^ 

* 

25 

* 

Larva  free, 

* 

« 

31 

* 

* 

Larva  free, 

Larva  free. 

4 

10 

Larva  very  large, 

* 

* 

* 

22 

Metam.  complete. 

Larva  large, 

Larva  large. 

Larva  small. 

8 

11 

Metam.  complete, 

* 

* 

28 

Metam.  complt. 

■se- 

10 

31 

Metam.  comp. 

3.  The  reproduction  of  some  sj^ecies  of  insects  before  they 
complete  their  metamorphosis  is  a  well-known  fact,  and  it  is  par- 
ticularly to  the  point  that,  in  many  of  them,  some  individuals  do 
attain  to  their  full  development,  while  the  many  do  not.  West- 
wood  says,*  "Two  British  species  of  this  family  (the  Reduviidae), 
Prostemma  guttula  and  Cor  anus  siibapterus,  are  interesting  on 
account  of  their  being  generally  found  in  an  undeveloped  state, 
the  latter  being  either  entirely  apterous  or  with  the  fore-wings 
rudimental,  although  occasionally  met  with  having  the  fore-wings 

*  Uhler  informs  me  that  Amyot's  asserted  color  characters  are  not  reliable. 


90  GENERAL  EVOLUTIOK 

completely  developed."  ''I  think,"  says  Spinola,  "that  the  pres- 
ence of  wings  and  their  development  depends  on  the  climate" ;  and, 
in  speaking  of  Oncocephalus  griseus,  he  says,  "  The  influence  of 
the  northern  climate  appears  to  have  arrested  the  development  of 
the  organs  of  flight.  It  will  be  seen  that  I  have  referred  else- 
where that  I  have  noticed  that  it  is  especially  in  hot  seasons  that 
certain  species  acquire  wings,  while  the  circumstance  noticed  re- 
specting the  ordinary  occurrence  of  winged  specimens  of  Micro- 
coelia  in  the  West  Indies  is  confirmatory  of  the  same  opinion." 

4.  It  is  now  known  that  certain  Orthoptera  do  not  get  through 
their  metamorphosis  in  time  for  the  period  of  reproduction,  and 
hence  never,  or  in  rare  instances  only,  develop  more  than  a  short 
distance  beyond  the  pupa  state. 

5.  My  friend  P.  R.  Uhler  tells  me  of  an  example  among 
Hemiptera  of  the  genus  Velia.  The  species  V.  rivulorum,  Fab., 
and  V.  curreiis,^  of  Europe,  are  only  distinguished  by  the  devel- 
opmental feature  of  the  presence  of  wings  in  one,  and  their  ab- 
sence in  the  other.  Another  species  of  the  tropical  region  of  the 
West  Indies,  Halobates  americanus,  Uhler,  is  furnished  with 
wings,  while  its  individuals,  which  occur  abundantly  in  North 
America,  have  been  generally  supposed  to  lack  them.  Individuals, 
however,  no  doubt  occur  whose  development  is  so  far  accelerated 
as  to  permit  them  to  acquire  wings  before  the  period  of  rej^roduc- 
tion,  since  one  such  has  been  found  by  Uhler. 

These  wing  characters  are  in  many  cases  generic,  it  aj^pears  to 
the  writer  ;  and  the  fact  that  they  differ,  without  corresponding 
specific  differences,  is  important  evidence  as  to  the  origin  of  the 
genera. 

6.  The  females  of  the  Lepidopterous  genus  Thyridopteryx 
never  develop  beyond  the  pupa  state,  according  to  the  same  au- 
thority, before  reproduction ;  they  are  reproducing  pupae,  so  far 
as  the  external  characters  concerned  in  metamorphosis  go.  In 
other  words,  the  latter  have  been  retarded,  while  the  reproductive 
system  and  others  have  progressed.  Now,  generic  characters  are 
seen  in  the  first,  not  in  the  last.  The  influence  of  the  males  is 
sufficient  to  prevent  more  than  a  part  of  the  offspring  from  being 
retarded  in  the  same  manner. 

I  have  selected  a  few  of  this  class  of  facts  which  have  come 
before  my  mind  during  the  present  writing,  as  drawn  mainly  from 

*  On  "  Insects,"  ii,  p.  493, 


ON"  THE  ORIGIN   OF  GENERA.  91 

my  own  experience.  How  many  more  of  the  same  purport  could 
be  found  by  search  through  the  great  literature  of  science,  or  in 
the  field  of  nature,  may  be  readily  imagined.  I  have  no  doubt 
that  the  field  of  entomology  especially  will  furnish  a  great  number 
of  evidences  of  the  theory  of  acceleration  and  retardation,  espe- 
cially among  the  insects  with  active  pupa3. 

Finally,  having  already  stated  the  law  according  to  which  these 
processes  naturally  take  place,  I  quote  the  following  significant 
language  of  Hyatt  in  the  above  quoted  essay  on  the  Cephalopoda, 
as  approaching  nearer  to  the  ^Maw  of  acceleration  and  retarda- 
tion "  than  anything  I  have  found  written.     He  says  : 

'^'^In  other  words,  there  is  an  increasing  concentration  of  the 
adult  characteristics  of  lower  species,  in  the  young  of  higher  sjoe- 
cies,  and  a  consequent  displacement  of  other  embryonic  features, 
which  had  themselves,  also,  previously  belonged  to  the  adult  peri- 
ods of  still  lower  forms." 

The  preceding  propositions  have  been  formulated  as  follows,  a 
few  additions  being  now  made  : 

I.  That  genera  form  series  indicated  by  successional  differences 
of  structural  character,  so  that  one  extreme  of  such  series  is  very 
different  from  the  other,  by  the  regular  addition  or  subtraction 
of  characters,  step  by  step.* 

II.  That  one  extreme  of  such  series  is  a  more  generalized  type, 
nearly  approaching  in  characters  the  corresponding  extreme  of 
other  series. 

III.  That  the  other  extreme  of  such  series  is  excessively  modi- 
fied and  specialized,  and  so  diverging  from  all  other  forms  as  to 
admit  of  no  type  of  form  beyond  it.  f 

IV.  That  the  peculiarities  presented  by  such  extremes  are 
either  only  in  part  or  not  at  all  of  the  nature  of  adaptations  to  the 
external  life  of  the  type.  J; 

V.  That  rudimental  organs  are  undeveloped  or  degraded  con- 
ditions of  the  respective  characters  developed  or  obliterated  in  the 
extreme  of  the  series. 

VI.  That  the  differences  between  genera  of  the  same  natural 
series  are  only  in  the  single  modifications  of  those  characters  which 
characterize  the  extreme  of  that  series. 

*  St.  Hilaire,  Owen,  Agassiz,  Dumeril. 
f  Dana  on  "  Cephalization  "  ;  Leconte. 

X  Owen  on  "  Cetacea,"   "  Trans.  Zool.   Soc,"  London,  1866,  p.  44.     Leconte  on 
"  Carabidae,"  "  Trans.  Amer.  Philos.  Soc.,"  1853,  p.  364. 


92  GENEEAL  EYOLUTIOK 

VII.  That  the  relations  of  the  genera  of  a  primary  series  are 
those  of  the  different  steps  in  the  development  of  the  individuals 
of  the  extreme  genus  ab  ovo  {von  Baer^  Agassiz)  (with  sometimes 
the  addition  of  special  adaptive  features  ?). 

VIII.  That  the  presence,  rudimental  condition,  or  absence  of 
a  given  generic  character  can  be  accounted  for  on  the  hypothesis 
of  a  greater  rapidity  of  development  in  the  individuals  of  the  spe- 
cies of  the  extreme  type,  such  stimulus  being  more  and  more  vig- 
orous in  the  individuals  of  the  types  as  we  advance  toward  the 
same,  or  by  a  reversed  imj^ulse  of  development,  where  the  extreme 
is  characterized  by  absence  or  "mutilation"  of  characters. 

IX.  And  that,  as  the  character  of  the  genus  at  the  period  of 
reproduction  of  its  species  is  that  which  is  per^^etuated  ; 

-  X.  So  the  character  of  the  genus  has  been  first  inferior,  then 
protean,  and  then  advanced,  as  the  metamorphosis  has  been  by  a 
retrograde  movement  in  time,  posterior  to,  at,  or  anterior  to  the 
period  of  reproduction. 

XI.  That  it  therefore  results  that  there  is  one  primary  struct- 
ural type  involved  in  such  a  series  of  species,  which  is  made  to 
present,  at  any  given  j)eriod  in  its  geologic  history,  that  appearance 
of  succession  of  genera  ordained  by  Creative  Power. 

d.  On  the  Origin  of  Inexact  Parallelism. 

The  hypothesis  can  only  be  demonstrated  in  case  of  exact  par- 
allelism. If  proved  in  these,  it  readily  accounts  for  the  cases  of 
inexact  parallelism,  which  are  of  course  in  any  single  period  vastly 
in  the  majority.  First  take  the  case  of  simple  inexact  parallel- 
ism. A  series  of  individ  uals  of  the  genus  Didocus  undergo  the 
metamorphosis  of  the  cranial  structure  earlier  and  earlier  in  life, 
commencing  by  completing  the  ossification  of  the  membrane  of 
the  fronto-parietal  region  in  full  age,  until  at  last  it  becomes  com- 
13leted  as  early  as  the  period  of  reproduction.  Heretofore  the 
adult  offspring  have  appeared  during  a  long  period,  invariably 
characterized  by  the  larval  cranium  ;  but  like  now  producing  like, 
this  development  springs  into  new  power,  and  the  offspring  ossify 
the  cranial  bones  far  earlier  than  their  immediate  predecessors ; 
in  a  word,  the  genus  Pelobates  has  been  created  !  At  this  state  of 
progress  Didocus  is  an  undeveloped  Pelobates. 

Let  us,  however,  suppose  the  '^acceleration  "  of  development 
of  the  cranial  bones  still  to  progress.  The  character  appears  now 
soon  after  the  ordinary  metamorphosis  has  been  passed,  and  now 


ON"  THE   ORIGIN   OF   GENERA.  93 

a  little  before.  The  identity  of  Diclocus  with  the  undeveloped 
Pelobates  is  thereupon  lost ! 

So  may  have  been  the  relations  between  Pelobates  and  Cul- 
tripes.  Pelobates  was  probably  once  identical  with  the  undevel- 
oped Cultripes ;  but  the  same  acceleration  has  concentrated  the 
characters  more  rapidly  than  the  other  larval  stages,  leaving  Pelo- 
bates behind. 

This  I  conceive  to  be  the  explanation  of  this  relation  :  when 
the  parallelism  is  inexact  by  two  steps,  as  in  Spea  to  Didocus,  by 
the  obliterated  ear  and  ossified  xiphisternum.  The  continued 
concentration  of  characters  has  been  carried  to  earlier  stages  till 
the  identity  exists  in  the  adult  state  of  neither  one,  but  at  a  pe- 
riod of  larval  life  of  botli,  shortly  preceding  the  adult  period  of 
the  lower.  The  relations  between  the  Amblystomidae  and  Pletho- 
dontidaB,  which  I  have  elsewhere  *  pointed  out,  have  probably 
had  their  origin  in  this  way. 

If  we  attempt  to  ]3rove  the  identity  of  the  modern  Mammalian 
foetal  circulation  with  that  of  the  modern  adult  fish,  we  may  find 
nearly  an  exact  parallel  in  this  respect,  as  it  is  the  basis  of  class 
distinction  ;  but  in  other  respects  the  identity  will  not  exist,  ren- 
dering the  parallel  inexact  or  remote.  The  structure  of  the  ori- 
gins of  the  aorta  is  at  one  time  identical  with  that  of  the  shark, 
with  one  exception  :  in  the  former  but  four  aorta-bows  appear  to- 
gether ;  in  the  latter  five.  In  the  former  the  first  disappears  as 
the  fifth  comes  into  being.  This  is  simply  a  continuation  of  ac- 
celeration. The  first  generalized  representative  of  the  Mammalia 
lost  the  first  aorta-bow  toward  the  latter  part  of  its  growth,  and 
became  the  next  genus  in  advance  of  the  selachian.  The  fact 
that  these  bows  do  not  appear  exactly  simultaneously,  but  rather 
successively,  renders  it  necessary  that  in  a  regularly  shortening 
period  of  possession  of  transitory  characters,  one  such,  as  the  ex- 
istence of  the  first  aorta-root,  should  vanish  before  the  appearance 
of  a  permanent,  the  fifth,  in  the  more  specialized  types,  where 
acceleration  reaches  its  maximum.  This  is  indicated  by  the  fact 
that  in  the  Batrachia,  where  the  acceleration  has  not  attained  so 
high  a  degree,  the  first  and  fifth  aorta-bows  co-exist  for  some  time, 
though  the  first  and  second  disappear  before  maturity. 

So  also  with  the  splitting  of  the  bulbus  arteriosus.  As  in  the 
Batrachia,  the  pulmonary  ductus  communis  only  is  to  be  sepa- 


*  "Jour.  Ac.  Nat.  Sci.,"  Phil.,  1866,  p.  100. 


94:  GENERAL  EVOLUTION. 

rated  ;  the  remaining  bulbus  is  divided  by  a  long  valve  or  incom- 
plete septum,  tracing  the  division  of  the  aorta-roots.  In  the  ser- 
pent (Rathke)  this  division  is  so  accelerated  as  to  appear  at  nearly 
the  same  time  as  the  septum  of  the  pulmonary  duct.  In  the 
mammal,  on  the  other  hand,  while  the  division  of  the  aorta-root 
takes  place  as  soon  as  in  the  last,  the  pulmonary  seiDtum  is  accel- 
erated so  as  to  appear  long  before  the  first  named.  Hence,  in  the 
septa  in  the  serpent,  the  singular  anomaly  seems  to  present  of 
the  mammal  passing  through  the  Batrachian  stage,  while  the  ser- 
pent, a  nearer  relative,  does  not.*  If,  however,  we  take  the  less 
typical  serpent,  we  will  find  the  aortic  septum  to  appear  a  little 
later,  thus  giving  the  Batrachian  type,  and  if  we  reverse  the  order 
of  time,  so  that  the  succession  becomes  one  of  retardations,  we 
wdll  find  the  same  known  ratio  will  bring  us  to  an  identity  under 
all  circumstances. 

This,  then,  is  the  explanation  of  the  divergence  and  want  of 
**  exact  parallelism,"  which  is  observed  in  comparing  the  develop- 
mental histories  of  all  tjipes  not  7nost  closely  allied.  It  has  not, 
according  to  our  theory,  always  been  a  divergence,  but  was  at  a 
prior  epoch  in  each  case  a  relation  of  "exact  parallelism,"  the 
lower  type  a  rej^ressed  higher ;  the  former  identical  with  one  of 
the  stages  of  the  latter.  But  the  process  which  has  produced  this 
relation,  continued,  has  of  necessity  destroyed  it,  so  that  the  ex- 
act parallelism  has  always  been  a  temporary  relation,  and  one 
shifting  over  the  face  of  the  system. 

III.    OF  HIGHER   GROUPS. 

First.     Comparison  of  the  contemporary. 

Having  now  admitted  a  developmental  succession  of  genera, 
and,  second,  that  this  has  progressed  more  rapidly  at  certain  times 
in  the  earth's  history  than  any  modification  of  specific  forms,  the 
hypothesis  already  broached  naturally  comes  up  :  Has  such  trans- 
formation of  types,  generic  or  higher,  tahen  place  in  any  degree 
simultaneously,  throughout  a  great  number  of  species  9  An  af- 
firmative answer  to  such  a  proposition  is  absolutely  necessary  to 
its  acceptance  as  expressing  the  phenomena  exhibited  by  geolog- 
ical succession  of  types.  Let  us  try  to  answer  the  question  put  in 
a  closer  form.     Have  the  same  species  been  transferred  from  one 

*  This  is  the  way  indeed  in  which  it  is  stated  by  Rathke,  "  Entwickelungsge- 
schichte  der  Natter,"  p.  164. 


ON  THE   ORIGm   OF   GENERA.  95 

geologic  epoch  to  another  by  a  change  of  generic  form  ;  and  has 
not  the  genus  been  transferred  from  one  epoch  to  another  under 
change  of  ordinal  type,  and  as  a  consequence  the  same  species  ? 

As  a  reply  I  propose  to  render  the  affirmative  of  the  first  of 
these  questions  highly  probable. 

Paleontology  only  will  be  able  to  answer  this  question  conclu- 
sively, though,  as  we  have  abundant  evidence  that  the  relations  of 
species  to  genera  and  other  higher  groups  were  the  same  then  as 
now,  we  may  look  to  the  present  status  as  furnishing  important 
evidence  on  the  subject.  We  are  turned  at  once  to  the  probable 
history  of  development  in  the  separate  zoological  areas  of  the 
earth's  surface.  The  question  may  be  asked,  Are  the  present  zo- 
ological regions  on  an  equal  plane  as  to  the  geologic  relations  of 
their  faunae,  or  are  they  related  as  the  different  subdivisions  of  a 
geologic  period  in  time  ? 

I  have  on  a  former  occasion  asserted  that  the  latter  of  these 
propositions  was  true.* 

a.  Of  Homologous  Groups. 

Naturally  following  the  admission  of  a  developmental  succes- 
sion of  organic  beings  is  the  question  of  its  relation  to  the  differ- 
ent surfaces  of  land  and  water  on  the  earth.  The  following  con- 
siderations bear  on  this  subject. 

Among  the  higher  groups  of  animals  can  be  detected  series 
^*  homologous "  on  the  same  principle  as  the  alcohols  (?  com- 
pound radicals)  and  their  derivatives  ;  and  the  component  types 
of  each  can  be,  and  have  been  in  many  instances,  shown  to  be 
''heterologous,"  as  are  the  ethers,  mercaptans,  aldehydes,  acids, 
etc.  Among  Mammalia  two  partly  homologous  series  have  been 
pointed  out,  Implacentialia  and  Placentialia ;  possibly  such  are 
the  types  Altrices  and  Prgecoces  among  Aves ;  of  a  lesser  grade 
in  this  class  are  the  parallel  series  of  Pullastrae  and  Gallinae,  of 
Clamatores  and  Oscines.  Among  tortoises  I  have  alluded  to  the 
Pleurodira  as  compared  with  the  remainder  of  the  order,  already 
parallelized  by  Wagler ;  and,  of  lesser  grades,  the  series  among 
Lacertilia  of  Acrodonta  and  Iguania,  parallelized  by  Dumeril  and 
Bibron,  and  of  Teidae  and  Lacertidae,  compared  by  Wiegmann.  I 
have  discovered  a  full  parallelism  between  the  Raniform  and  Arcif- 
erous  Anura.  It  is  carried  out  between  the  Characini  and  a  group  of 
remaining  Physostomous  Fishes,  perhaps  not  yet  well  defined  ;  it 

^  On  "  Arciferous  Anura,"  "  Journ.  Ac.  Nat.  Sci.,"  1866,  p.  108. 


96  GENERAL  EVOLUTION. 

is  exhibited  between  tlie  orders  Diptera  and  Ilymenoptera  among 
insects.  None  of  these  comparisons  can  be  allowed,  of  course, 
without  the  most  searching  anatomical  and  embryological  analysis. 

This  heterology  i^  what  Swainson  and  others  called  ''^analogy" 
as  distinguished  from  affinity.  It  generally  relates  genera  of  dif- 
ferent zoological  regions.  Mimetic  analogy,  on  the  contrary,  re- 
lates genera  of  the  same  region  ;  it  is  a  superficial  imitation  which 
has  occurred  to  critical  biologists,  and  is  of  much  interest,  though 
as  yet  but  little  investigated.  It  has  as  yet  been  observed  in  ex- 
ternal characters  only,  but  occurs  in  internal  also  ;  it  has  been 
accounted  for  in  the  first  case  by  the  supposed  immunity  from 
enemies  arising  from  resemblance  to  wxll-defeuded  types.  No 
such  explanation  will,  however,  answer  in  the  latter  case.  I  be- 
lieve such  coincidences  express  merely  the  developmental  type 
common  to  many  heterologous  series  of  a  given  zoological  **  re- 
gion "  ;  this  will  be  alluded  to  a  few  pages  later. 

We  naturally  inquire.  Is  there  anything  in  the  food,  the  vege- 
tation, or  the  temiDcrature  to  account  for  this  aj^parent  diversity 
in  the  different  regions  ?  Are  there  not  carnivora,  herbivora, 
seed-eaters,  insectivores,  and  tree-climbers,  where  game  and  grass, 
seeds  and  insects  and  forests  grow  the  world  over  ?  We  answer 
undoubtedly  there  are,  and  these  adaptations  to  food  and  climate 
are  indeed  as  nothing  in  the  general  plan  of  creation,  for  every 
type  of  every  age  has  performed  these  functions  successively. 

3.  Of  Heterology.^ 

This  relation  will  be  exhibited  by  a  few  examples  from  groups 

known  to  the  writer,  commencing  with  the  Batrachia  anura. 

Raniformes.  Arciferi. 

External  metatarsal  free. 

Aquatic.  Rana.  Pseudis. 

Metatars.  shovel,  Hoplobatrachus.  Mixophyes. 

External  metatarsal  attached. 

Feet  webbed. 
Metatars.  shovel.  Pyxicephalus.  Tomopterna. 

*  Some  of  the  cases  below  cited  as  heteroloiry  I  believe  to  be  trulv  of  this  char- 
acter ;  but  some  others  are  probably  not  such,  but  are  merely  series  of  genera  pre- 
senting similar  structural  peculiarities  as  consequences  of  the  operation  of  identical 
laws.  I  would  place  under  this  head,  and  withdraw  from  the  homologous  class,  the 
families  of  Lacertilia  Leptoglossa,  Diploglossa^  and  Typhlophthalmi^  those  of  the  Old 
and  New  "World  Quadrumana  and  those  of  Cephalopoda.  These  distinct  modes  of 
origin  of  corresponding  forms  have  been  recently  termed,  by  Lancaster,  homogeny 
in  the  ease  of  homologous  groups,  and  homoplassy  when  the  imitative  types  are  on 
distinct  lines.     (Ed.  1886.) 


PLATE  n. 


PLATE  II. 

Figures  of  Lizards  of  the  family  Iguatiidfe  to  be  compared  with  a  homologous 
series  of  Agamidae  represented  in  Plate  Ila.     The  species  are  : 

Fig.  1.  Basiliscus  phimifrons  Cope,  Costa  Rica.     From  Cope. 

Fig.  2.  Iguana  tuhercidata  Linn.,  South  America.  From  the  "  Standard  Xatural 
History." 

Fig.  3.  Crotaphytus  wislizeni  B.  G.,  Sonoran  Region  of  North  America.  From 
Baird. 

Fig.  4.  Phy maiurus  pallumaGTSLV.,  ChWi.     From  Bell. 

Fig.  5.  Fhrynosoma  cornutum  Harl.,  Texas.    From  "  Standard  Natural  History." 

PLATE   Ila. 

Figures  of  Lizards  of  the  family  Agamidae  which  form  a  homologous  series  with 
the  Iguanidse  represented  on  Plate  11. 

Fig.  1.  Lophura  arnboinetisis  Schloss.,  Amboina.     From  "Wagler. 

Fig.  2.  Physignathus  mentager  Giinther,  Siam.     From  Giinther. 

Fig.  3.  Liolepis  hellii  Gray,  China.     From  Dumeril  and  Bibron. 

Fig.  4.    Uromasiix  spinipes  Cuv.,  Arabia.     From  Guerin. 

Fig.  5.  Moloch  horridus  Gray,  Austi-alia.     From  "  Standard  Natural  History." 


ON  THE  OKIGIN^   OF   GENERA. 


97 


Raniformes. 

Arciferi. 

Arboreal ;  vom.  teeth. 
Subarboreal. 

Leptopelis. 
Hyperolius. 
Hylambates, 

Hvla. 

Hylella. 

Nototrema. 

Terrestrial. 

"          spurred, 

Feet  not  webbed. 
Cassina. 
Hemimantis. 

Cystignathus. 
Gomphobates. 

Comparmg  the  genera  in  a  general  physiological  sense,  we  may 
parallelize  further. 

Aquatic,  with  digital  dilatations. 

Heteroglossa, 

Arboreal :   cranium  hy-   )    -r,  ,        ,  ^ 

perostosed.   \    ^oljved^tes. 

"  cranium  free.     Rhacophorus. 


Acris. 


Trachycephalus. 

j  Hyla. 

(  Agalychnis. 


The  same  kind  of  parallels  exists  between  the  primary  groups 
of  the  Testudinata,  as  follows  : 

Crtptodira.  Plefrodira. 

Five  complete  pairs  of  bones  across  the  plastron. 

Pleurosternidae.  Stemothseridae. 

Four  pairs  of  bones  across  plastron ;  not  more  than  two  phalanges  on  all  toes. 

Testudinidae.  Pelomedusidae. 

Three  phalanges  on  most  digits ; 
Zygomatic  arch  ;  no  parieto-mastoid. 

Eraydidae.  Podocneraididae, 

Temporal  fossa  over-roofed  hj  parietal. 

Macrochelys.  Podocnemis. 

No  zygoma ;  a  parieto-mastoid  arch. 

Hydraspididae. 


* 


* 


* 


If  we  compare  the  peculiarities  of  generic  structure  merely 
with  reference  to  their  adaptation  to  the  animals'  habits,  we  will 
see  the  following  : 

Cryptodira. 
Feet  reduced  for  terrestrial  progress. 

Testudinidae. 
Feet  normal. 

Anterior  lobe  of  sternum  movable. 

Cistudo. 
Cinosternum. 
Anterior  lobe  fixed. 
Neck  very  elongate. 

Trionychidae. 
Neck  shorter ;  aquatic. 
Temporal  fossa  open. 

Emydidae  in  gen. 
Temporal  fossa  over-roofed. 

Cheloniidae. 


Pleurodira. 
Pelomedusidae. 

Sternothaerus. 

Chelodina. 

Hydraspididae. 
Podocnemis. 


The  parallels  between  the  genera  of  the  American  Iguanidae 
and  the  Old  World  Agamidae  are  similarly  quite  close.     They  are 
shown  on  Plates  II  and  II  a. 
1 


98 


GENERAL  EVOLUTION. 


Abdominal  ribs. 


Iguanidje. 
Polvchrus. 


AGAMIDiE. 


No  abdominal  ribs. 

llibs  greatly  prolonged  into  a  lateral  wing. 

*        *  Draco. 

Ribs  not  prolonged. 

Arboreal  types,  generally  compressed. 

A  dorsal  and  caudal  fin  supported  by  bony  rays. 

Basiliscus  (no  lem.  pores).     Lophura  (pores). 

No  vertebral  fin. 

No  femora]  pores. 
Form     slender,    scales     in     Calotes. 

equal  series.  Bronchocc 

Form    elongate ;    eyebrows 

Gonyocephalus. 


cela.  ) 


Lasmanctus. 


elevated,  tail  compressed. 
Form    stouter,    scales    less 


regular. 


Hypsibates. 

Femoral  pores. 

Brachylophus. 


Ophryoessa. 
Tiaris. 


Diporophora. 

Pliysignathus. 
*        * 


Low  crested;    small  hyoid 

disk. 
High  crested;    large  hyoid 

disk.  Iguana. 

Tail  with  spinous  whorls.         Cyelura. 

Terrestrial  types  of  flattened  form. 

Femoral  pores. 
Tail  with  whorls  of  spiny 

scales.  Hoplocercus.  Uromastix. 

Tail    long,    simple;    scales 

small.  Crotaphytus.  Liolepis. 

Tail  simple,  scales  large.  Sceloporus.  *     * 

No  femoral  pores  ;  preanal  pores. 

Tail  with  whorls  of  spines.  *         *  Stellio. 

Tail   simple,  not   elongate, 

ear  open.  Proctotretus.  Agama. 

Neither  femoral  nor  anal  pores. 

Much  flattened,  tail  short,  scales  irregular. 

Ear  exposed.  Phrynosoma.  Moloch. 

Ear  concealed.  (Doliosaurus,  s.  g.)  j  Segd'Sus!'"'' 

A  similar  parallel  may  be  drawn  between  the  American  Teidas, 
and  the  Old  World  Lacertidae,  and  in  fact  between  all  the  families 
of  the  Lacertilia  Leptoglossa.  I  have  added  to  these  for  compari- 
son two  families  of  the  Typhlophthalmi.  Each  family  embraces 
one  or  more  series,  and  these  exhibit  a  remarkable  similarity  in 
the  relative  development  of  the  limbs  and  digits  ;  among  the 
higher  groups  the  parallelisms  lie  in  the  arrangement — as  greater 
or  less  separation — of  the  head  shields.  The  Scincidae  are  cosmopo- 
lite ;  the  Gymnophthalmidae,  which  have  the  eyelids  of  their  foe- 
tus, are  Australian  ;  the  Sepsidas,  either  larval  or  senile  in  head 
shields,  are  mostly  Ethiopian. 


ON  THE   ORIGIN"  OF  GENERA. 


99 


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100  GENERAL  EVOLUTION. 

The  first  comparison  of  these  groups  was  made  by  Wiegmann 
(Herpetologia  Mexicana),  who  employed,  however,  only  the  Scin- 
cidse  and  Lacertidae,  and  could  not  include  the  many  types  made 
known  since  his  day. 

From  the  class  Aves  I  have  selected  only  the  homologous  series 
of  the  Clanatorial  and  Oscine  Passeres.  Naturalists  more  fully 
acquainted  with  the  genera  could  probably  increase  the  examples 
of  heterology  largely.  Each  group  furnishes  us  with  carnivo- 
rous, insectivorous,  and  frugivorous  forms  ;  each  with  walkers, 
climbers,  and  sedentary  genera  ;  each  with  butcher-birds,  thrushes, 
warblers  (not  in  song  !),  wrens,  and  fly-catchers.  Each  and  all  of 
these  types  are  teleologically  necessary  to  any  country  complete  in 
the  wealth  of  nature,  and  to  each  geological  period. 

Clamatores.  Oscines. 

I.  Tree-climbers,  with  long  hind  toe  and  tail  feathers  stiffened  and  acute. 

Dendrocolaptidce.  Certliiidce. 

II.  Terrestrial  in  part,  with  the  tertials  as  long  as  the  primary  quills. 

Geobatidce.  ITotacillidce. 

III.  Tree-perchcrs  with  hooked  bill,  graduating  from  powerful  to  medium  and 
slender. 

JPbrmicariidce  Turdidce. 

Thamnophilus.  Bill  strongest,  hooked.  Lnnius. 

Formicarius.  "    moderate.  Turdus. 

Formicivora.  "    weak.  iSylvia. 

Rhamphoccemus.  "    slender  (wrens).  Troglodytes. 

IV.  Fly-catchers  with  flat  bill  and  weak  legs ;  wait  for  their  prey  and  take  it  on 
the  wing. 

Tyrannidve.  Muscicapa  et  aff. 

V.  Flat-billed  berry  and  fruit  eaters. 

Cotingidce.  Bomhycillidce. 

From  the  Mammalia  the  well-known  series  of  the  Marsupialia  and  Placentialia 
may  be  chosen. 

Placentialia.  Marsupialia. 

I.  Toes  unguiculate,  in  normal  number ;  sectorial  teeth ;  i.  e.,  one  or  more  molars 
with  one  or  no  internal  tubercles  ;  canines  strong : 

Carnivora.  Sarcophaga. 

I.  Digitigrade. 
Toes  5 — 1. 

True  molars  §  (upper  incisors  more  numerous  in  some). 
Amphicyon.  Thylacinus. 

II.  Plantigrade ;  molars  tubercular. 
a.  Posterior  molars  f . 

*  *  Dasyuridae. 

aa.  Posterior  molars  |. 
Ursidffi.  *  * 

II,  Toes  unguiculate ;  molars  with  more  than  one  row  of  pointed  tubercles ;  canines 
weak  or  none ;  incisors  large. 


ON  TEE   ORIGIN  OF  GEKERA. 


101 


Insedivora. 


Gymnura. 
Cladobates. 


a.  Tubercular  molars  |,  toes  4 — 5. 
Tail  naked. 

Tail  hairy. 


Entomophaga. 


Didelpbys. 
Myoietis 


rV.  Molars  with  transverse  crests,  no  canines ;  tusk-like  incisors  ;  pairs  of  limbs  of 
similar  proportions. 

Froboscidia.  Diprotodontidfe. 

Two  inferior  incisors  ;  molars  with  two  cross-crests ;  size  huge. 
a.  Two  rudimental  lateral  incisors  above. 

*  *  Diprotodon. 

aa.  ?  One  pair  of  incisors  only  above ;  a  trunk. 
Dinotherium. 

Y.  No  canines ;  two  pairs  of  cutting  incisors. 

«.  Three  true  molars. 
Rodentia.  *  * 

aa.  Four  true  molars. 

*  *  Rkizophaga. 

The  parallels  are  in  this  case  very  imperfect  in  details,  and  but 
few  worthy  of  the  name  can  be  made.  They  are,  however,  illus- 
trative of  a  remote  heterology,  sufficiently  remarkable  to  have 
claimed  the  notice  of  naturalists  for  many  years. "^  I  also  have 
little  doubt  but  that  future  paleontological  discoveries  will  in- 
crease the  number  of  parallels,  f  and  bring  to  light  truly  heterolo- 
gous generic  terms  of  the  Marsupial  series.  Predictions  of  this 
kind  have  been  on  many  occasions  fulfilled  (e.  g.,  some  of  D'Or- 
bigny's  among  the  Cephalopoda),  and  I  look  with  confidence  to 
the  ultimate  demonstration  of  that  heterology  here  which  has 
been  already  seen  in  the  Batrachia  and  Reptilia. 

The  homologous  groups  of  the  Catarrhine  and  Platyrrhine 
Quadrumana  are  measured  as  follows  : 


CatarrJiini. 

Platyrrhini. 

Tailless. 

Andropithecus. 

* 

Simla. 

* 

Hylobates. 

* 

Tail  short. 

Cynocephalus. 

* 

Macacus. 

Brachyurus. 

Long  tail. 

Thumb  developed. 

Cercopithecus. 

Lagothrix. 

Mycetes. 

Thumb  rudimental. 

Semnopithecus. 

Brachyteles. 

Thumb  none. 

Colobus. 

Ateles. 

*  We  owe  very  many  observations  on  the  Marsupials  to  Owen. 

f  The  extinct  carnivorous  family  of  the  Nimravidae  which  forms  a  homologous 
series  with  the  cats  (Felidae)  was  discovered  by  the  writer  some  years  after  this  was 
written.     (Ed.  1886.) 


102  GENERAL  EVOLUTION". 

I  append  two  homologous  series,  represented  by  the  Nautilea 
and  the  Ammonites  of  the  Tetrabranchiate  Cephalopoda,  which 
are  distinguished,  the  first  by  the  simple  septa  and  the  siphon 
central  or  marginal  ventral  ;  and  the  second  by  the  complex  and 
folded  septa  and  siphon  central  or  marginal  dorsal.  The  parallel- 
isms have  been  noted  by  Barrande,  Bronn,  and  many  concholo- 
gisfcs,  who  can  furnish  a  much  more  full  table  than  the  following, 
from  the  most  recent  sources  : 

Nautili.  Ammonites. 

A.  The  shell  straight,  unwound. 

Orthoceras.  Baculites. 

B.  The  shell  more  or  less  curved  or  wound, 
c.  Simply  curved. 

Cyrtoceras,  )  Toxoceras. 

Phragmoceras,        ) 

aa.  A  more  or  less  straight  portion,  folded  on  the  remainder. 
j3.  Folded  poition  in  close  contact  with  remainder. 
Ascoceras.  Ptychoceras. 

/3/3.  Folded  portions  not  in  contact. 
V  ?  Hamites. 

aaa.  One  extremity  spirally  wound,  the  volutions  not  in  contact. 
/?.  Extremity  of  the  shell  prolonged  beyond  the  wound  portion. 
Lituites.  Ancyloceras. 

)8/3.  Extremity  not  prolonged  in  a  line. 
7  The  spiral  flat. 
Gyroceras.  Crioceras. 

yy.  The  spiral  elevated  (heliciform), 
Trochoeerus.  Turrilites. 

aaaa.  Spiral  turns  of  the  shell  in  contact. 

p.  Er.tremity  prolonged  in  line  beyond  the  spiral. 
*  *  Scaphites. 

)S/3.  Extremity  not  prolonged  beyond  spiral. 
Nautilus.  Amrhonites. 

We  may  now  consider  the  question  of  the  origin  of  these  higher 
groups.  In  the  first  place,  we  must  lay  down  the  proposition  that 
the  characters  which  constitute  groups  '' higher ''^  iii  the  compari- 
son of  ranh  (we  do  not  of  course  mean  higher  in  the  same  line,  as 
we  say  higher  genus  in  a  family,  or  higher  order  in  a  class)  are 
such  solely  from  their  bei7ig  more  comprehensivs,  or  i^esent 
throughout  a  greater  range  of  species. 

What  is  true,  therefore,  in  respect  to  characters  of  genera,  is 
likely  to  be  true  in  respect  to  characters  of  higher  groups,  such 
as  we  have  been  considering  in  the  preceding  pages.  Believing, 
then,  that  a  new  genus  has  been  established  by  the  transition  of  a 
number  of  species  of  a  preceding  genus  in-order,  without  neces- 
sary loss  of  specific  characters,  I  think  the  same  process  may  have 
established  the  suborders  and  orders  in  question.  That  is,  that  a 
large  numiber  of  genera  have  near  the  same  time,  in  past  or  pres- 


01^  THE   ORIGIN-   OF   GENERA.  103 

cnt  geological  Idstory,  passed  into  another  suborder  or  order  hii 
the  assumption  or  loss  of  the  character  or  characters  of  that  to 
or  from  luhich  they  ivere  transferred,  and  that  without  necessary 
loss  of  their  generic  characters. 

I  will  cite  a  probable  case  of  this  kind,  the  facts  of  which  I 
have  already  adduced. 

It  has  been  shown  above  that  the  genera  of  six  of  the  fami- 
lies of  the  Batrachia  anura  form  series  characterized  by  the  suc- 
cessive stages  of  ossification  of  the  skull,  terminating  in  a  der- 
moossified  condition,  with  over-roofed  temporal  fossae.  That  in 
nearly  all  the  other  families  similar  relations  between  genera  exist, 
but  are  nowhere  carried  so  far.  The  character  attained  by  all 
the  first  series  is  now  only  generic  ;  but  should  all  the  genera  of 
each  of  the  six  families  assume  this  character  in  time,  as  is  neces- 
sary in  accordance  with  a  development  hypothesis,  it  would  at 
once  possess  a  new  and  higher  importance,  and  would  become  or- 
dinal or  otherwise  superior.  It  would  define  a  series  homologous 
with  all  those  types  which  had  not  attained  it.  This  character 
of  the  over-roofing  of  the  temporal  fossae  has  actually  attained  a 
family  significance  among  the  Testudinata — e.  g.,  as  defining  the 
marine  turtles ;  and  similar  characters  are  found  by  Owen  to 
characterize  the  Labyrinthodontian  order  of  Batrachia.* 

Agassiz  has  pointed  out  a  similar  and  more  extended  case,  in 
the  lieterocercal  and  Homocercal  ganoids.  Had  we  not  so  many 
of  the  closest  approximations  between  members  of  these  groups, 
they  would  stand  in  the  systems  as  two  great  homologous  series, 
with  their  contained  heterologous  genera.  As  it  is,  these  heter- 
ologous terms  or  genera  are  evidently  so  nearly  allied  that  Agassiz, 
in  the  "  Poissons  Fossiles,"  has  thought  it  best  to  arrange  the  latter 
together,  thus  instituting  a  system  transverse,  as  it  were,  to  the 
other.  This  may  be  necessary,  since  Kolliker  points  out  transi- 
tional forms,  and  perhaps  certain  types  may  have  begun  to  aban- 
don the  heterocercal  form  near  the  period  of  reproduction,  pro- 
ducing offspring  somewhat  protean  in  character,  preparatory  to 
an  earlier  appearance  and  consequent  permanence  of  the  homocer- 
cal type.  This  is  to  be  derived  from  the  history  of  the  metamor- 
phosis of  Amblystoma. 

In  the  same  manner  the  development  of  the  convolutions  of  the 
brain  does  not  define  groups  of  the  highest  rank,  since  it  pro- 

*  The  roof  here  alluded  to  by  Owen  includes  some  two  distinct  bones  not  known 
in  the  arch  of  the  Anura,  and  therefore  different. 


104  GENERAL  EVOLUTION. 

gresses  chiefly  during  the  later  periods  of  embryonic  life,  and  is 
therefore  a  '^developmental  character."  Owen  has  endeavored  to 
distinguish  the  primary  divisions  of  Mammalia  by  the  character 
of  these  convolutions,  whereas  they  really  define  only  the  sub- 
groups of  the  orders.  Eor  we  have  Lissencej^halous  (smooth- 
brained)  monkeys — certain  lemurs — and  smooth-brained  Eumi- 
nants — i.  e.,  the  extinct  Brachyodon  and  Anoplotherium,  accord- 
ing to  Lartet  and  Gratiolet.  The  lowest  types  of  the  existing 
smooth-brained  Mammalia,  including  es^^ecially  those  wdth  no 
or  rudimental  corpus  callosum,  the  Marsupials,  are  also  distin- 
guished by  the  non-development  of  the  deciduous  teeth  *  (except- 
ing one  premolar).  If  now,  through  some  topographical  change, 
the  whole  series  of  Mammalia  between  the  smooth-brained  and 
convolute-brained  were  lost  to  us,  as  by  the  elevation  of  a  region, 
and  the  absence  of  favorable  localities  or  bodies  of  water  for  the 
preservation  of  their  remains,  we  would  have  to  study  two  homol- 
ogous groups,  with  the  heterologous  terms  of  each  corresponding 
with  each  other,  as  do  now  the  genera  of  the  Clamatores  and  Os- 
cines  of  the  Arcifera  and  Eaniformia,  etc. 

In  the  same  way  the  characters  defining  Iraplacental  Mam- 
malia will  be  found  transitional  in  some  type,  and  this  great  se- 
ries, homologous  with  the  Placentals,  will  have  to  be  placed  in 
closer  connection,  in  its  genera,  with  the  series  of  the  latter,  with 
genera  of  the  same,  perhaps,  now  extinct. 

y.    Of  Mimetic  Analogy, 

It  has  been  often  remarked  that  the  animals  of  the  Equatorial 
Ethiopian  region  were  very  generally  of  smoky  and  black  colors. 
This  is  remarkably  the  case,  and  the  peculiarity  of  the  genus  Homo 
in  this  respect  is  shared  by  birds,  reptiles,  and  fishes  in  a  consider- 
able degree.  This  can  not  be  traced  to  the  effect  of  torrid  climate, 
for  the  same  latitudes  in  India  and  the  Malaysian  Archipelago, 
and  in  South  America,  do  not  produce  such  colors. 

The  similarity  in  color  of  desert  types  has  also  been  remarked. 
The  gray  sand-hue  so  well  adapted  for  concealment  is  universal, 
with  few  variations,   in  the  reptiles  of  the  Tartar  and  Arabian 

*  This  I  have  alluded  to  as  the  non-development  of  the  permanent  series ;  the 
homology  of  the  dental  system  of  Marsupials  appears,  however,  to  be  with  the  latter 
and  not  with  the  milk  series.  See  "Flower,"  "Trans.  Roy.  Soc,"  1867.  (Wortman 
now  denies  the  correctness  of  Flower's  view,  and  demonstrates  that  the  milk  series 
is  primitive.     See  "Encyclopaedia  of  Dentistry,"  1886.     Ed.  1886.) 


Plate  ni 


T.  Sinclair.  &  Son,  Phila 


MIMETIC    ANALjOGY. 


Plate   IIIc; 


T.  Siriclait-.  &  Son.Fhiia 


MIMETIC    ANALOGY. 


PLATE   III. 

Fig.  1.  Flaps  dumerili  Jan;   New  Gra- 
nada. 
Fig.  2.  Elaps  Icmniscatus  L. ;  Brazil. 

Fig.  8.  Flaps  semipartitus  D.  and    B  ; 

New  Granada. 
Fig.  4.  Flaps  psyche  Daud. ;  Brazil. 

Fig.  5.  Flaps  corallinu^  Linn. ;  Brazil, 
Central  America. 

Fig.  6.  Ophibohis  doliatus  Linn. ;  South- 
ern United  States  to  Central 
America. 


I 


PLATE   III«. 

Fig.  1.  Pliocercus  elapoidcs  Co\)Q ',  Mex- 
ico. 

Fig.  2.  Oxyrrliopus  trigeminus  Tt.  and 
B.;  Brazil. 

Fig.  3.  PUocercus  etiryzomcs  Cope  ;  New 
Granada. 

Fig.  4.  Frythrolamprus     cscidapil     L.  ; 

Brazil. 
Fig.  5.   Cemophora      cocci7ica      Blum.  ; 

Southern  United  States. 
Fig.  6.  Frythrolamprus       vcnustissimus 

Neuw. ;  Brazil,  Ccntr'l  America. 


The  species  placed  opposite  to  each  other  present  similar  patterns  of  coloration. 
Figs.  3  and  4,  Plate  III,  correspond  with  Fig.  3,  Plate  III«,  and  Fig.  6,  Plate  III, 
with  Figs.  5  and  6,  Plate  Ilia.  The  species  inhabit  the  same  regions,  more  or  less 
exactly,  excepting  the  two  Figs.  1.  The  Elapjs  dumerili  would  have  been  better  re- 
placed by  a  variety  of  the  Elaps  fidvlus  of  Mexico,  which  has  the  red  spaces  black 
bordered ;  but  a  good  colored  plate  was  not  accessible  at  the  time  the  drawing  was 
made.  All  the  figures  are  copied  from  Jan's  "  Iconographie  Generale  des  Ophi- 
diens  "  ;  and  the  colors  of  such  as  I  have  not  at  hand  for  reference  ( Ekqjs  dumerili, 
Flaps  semipartitus,  and  Flaps  psyche)  are  derived  from  the  "  Erpetologie  Generale," 
and  from  Jan's  "Prodrome."  The  species  of  Elaps  are  poisonous;  the  others  are 
harmless. 


ON  THE   ORIGIN  OF  GENERA. 


105 


deserts,  the  great  Sahara  and  the  sands  of  Arizona  and  California. 
There  is  also  a  tendency  to  produce  spiny  forms  in  such  places  • 
witness  the  Stellios  and  Uromastix  and  Cerastes  of  the  Sahara, 
the  Phrynosomas  and  horned  rattlesnake  of  Southwestern  Amer- 
ica. The  vegetation  of  every  order,  we  are  also  informed,  is  in 
these  situations  extremely  liable  to  produce  spines  and  thorns. 

The  serpents  of  the  Neotropical  region  furnisli  remarkable 
illustrations  of  mimetic  analogy.  All  the  species  of  the  genera 
Elaps,  Pliocercus,  Erythrolamprus,  and  many  of  those  of  Oxyr- 
rhopus, Ophibolus  and  Rhabdosoma  are  ornamented  with  black 
and  yellow  rings  on  a  crimson  ground.  The  species  of  all  these 
genera  are  harmless,  except  in  the  case  of  Elaps,  which  is  venom- 
ous. We  may  give  for  this  genus,  as  the  most  varied,  the  follow- 
ing range  of  variation  in  coloration  : 


Pairs  of  black  rings  ; 

Single  black  rings^far  apart. 

Single  black  rings,  very  close. 

Oplieomorplius  mimus.  d 
Erythrolamprus   venustissi- 

Elaps  corrallinus.  b 

nigrocinctus.  c 
Pliocercus  equalis.  c 

Oxyrrhopus  ? 
Erythrolamprus    albostola- 

Elaps  mipartitus,  d 

Pliocercus  euryzonus.  d 

Oxyrrhopus  petolarius.  d 
Scolecophis  zonatus.  a 

mus.  a 

tus.  b 

Ophibolus  polyzonus.  a 
Xenodon  bicinctus.  b 

Leptognathus  anthracops.  a 

Single  black  rings  loith  faint 
laterals. 

Black  rings  in  threes. 

Sifigle     black    rings    about 
equal  to  intervals. 

Elaps  fulvius. 

elegans.  a 

Elaps  lemniscatus.  b 

Elaps. 

Pliocercus  dimidiatus.  a 

Pliocercus  elapoides.  a 
Procinura  semula.  a 

Oxyrrhopus  trigeminus,  b 
Pliocercus  elapoides  var.  a 

Catostoma  semidoliatum.  a 
Oxyrrhopus  sebae.  d 
Ophibolus  pyrrhomelas.  h 
Chionactis  occipitale.  h 
Sonora  semiannulata.  h 
Contia  isozona.  h 
Chilomeniscus  epliippicus.  h 

Species  a,  from  Mexico  and  Central  America.     (Two  species  are  now  added,  1886.) 
"       b,      "     Brazil,  Venezuela. 
"        c,      "     Central  America. 
"        d,      "     western  side  of  Andes. 
"        h,      "     Arizona  and  Sonora. 

Many  of  the  species  in  the  same  column  are  exceedingly  simi- 
lar, and  some  have  little  (perhaps  nothing)  to  distinguish  them  but 
generic  characters.  The  most  similar  are  almost  always  from  the 
same  sub-region.*   These  facts  are  illustrated  in  Plates  III  and  III  a. 


*  Similar  parallels  exist  between  the  Mexican  species  of  Rhadinsea,  Conophis, 
and  Erythrolamprus  (  =  Coniophanes).     (Note,  1886.) 


106  GENERAL  EVOLUTION. 

Similar  analogies  have  been  pointed  out  by  Bates  among  the 
Lepidop'tera  of  Brazil,  and  by  Wallace  among  those  of  Borneo 
and  Celebes,  etc.  I  call  attention  to  these  authors  here  without 
copying  them,  as  they  will  repay  perusal  in  the  originals. 

A  case  of  analogy  which  may  belong  to  this  class  is  that  of  the 
three  genera  Chelys  among  tortoises,  Pipa  among  frogs,  and  As- 
predo  among  Siluroid  fishes,  species  of  which  inhabit  at  the  same 
time  the  rivers  of  Guiana.  The  crania  of  these  genera  are  simi- 
larly excessively  flattened  and  furnished  with  dermal  aj^pendages, 
and  their  eyes  are  very  minute.  The  singular  similarity  need  only 
be  mentioned  to  those  familiar  with  these  genera,  to  be  recognized. 

The  bearing  of  the  mimetic  analogy,  on  the  question  of  transi- 
tion of  types  in  the  developmental  hypothesis,  is  its  demonstra- 
tion of  the  independence  of  generic  and  specific  characters  of  each 
other,  which  may  suggest  the  possibility  of  the  former  being 
modified  without  affecting  the  latter. 

These  facts  might  have  been  introduced  under  Section  II  a,  but 
they  illustrate  the  general  laws  of  the  present  section. 

IV.    OF   KATUKAL   SELECTIO^h". 

a.  As  affecting  Class  and  Ordinal  Characters. 

The  second  law  which  may  be  supposed  to  have  governed  a 
descent  with  modification,  in  the  production  of  existing  genera, 
is  the  force  which  the  environment  exercises  in  permitting  or  for- 
bidding the  existence  or  persistence  of  new  forms.  The  forms 
which  survive  are  supposed  to  have  done  so  by  virtue  of  their  su- 
perior adaptation  to  their  environment.  This  is  the  ''  natural 
selection  "  of  Darwin. 

That  this  law  is  subordinate  to  the  one  first  propounded  must, 
I  think,  be  evident  to  any  one  who  studies  the  assumed  results  of 
the  workings  of  both,  as  seen  in  the  characters  of  genera.  It  is 
sufficiently  well  known  that  the  essential  features  of  a  majority  of 
genera  are  not  adaptive  in  their  natures,  and  that  those  of  many 
others  are  so  slightly  so,  as  to  offer  little  ground  for  the  supposi- 
tion that  this  necessity  has  preserved  them. 

Both  laws  must  be  subordinate  to  that  unknown  force  which 
determines  the  direction  of  the  great  series.  If  a  series  of  sup- 
pressions of  the  nervous  and  circulatory  systems  of  beings  of  com- 
mon birth  produced  the  "synthetic  "  predecessors  of  the  classes 
of  Vertebrata,  the  direction  toward  which  the  highest  advanced, 


ON  THE   ORIGIN   OF  GENERA.  107 

or  its  ultimate  type,  can  be  only  ascribed  as  yet  to  the  divine  fiat. 
So  far  as  we  can  see,  there  is  no  reason  or  law  to  produce  a  prefer- 
ence for  this  direction  above  any  other  direction. 

If  from  these  fixed  bases  descendants  have  attained  to  succes- 
sive stations  on  the  same  line  of  progress,  in  subordinate  features 
of  the  nervous  and  circulatory  systems,  constituting  the  *^  syn- 
thetic "  predecessors  of  the  orders  in  each  class,  the  type  finally 
reached  seems  to  rest  on  no  other  basis  than  the  pleasure  of  the 
Almighty. 

(i.  As  affecting  Family  Characters. 

If  from  the  single  species  generalizing  a  modern  order  we  at- 
tempt to  deduce  synthetic  predecessors  of  existing  families,  we 
find  some  difficulty,  if  we  attempt  to  see  in  these  stages  a  uniform 
succession  of  progress.  A  suppression  of  some  features,  and  ad- 
vance in  others,  in  one  and  the  same  individual  up  to  the  period 
of  reproduction,  would  produce  offspring  divergent  from  the  start, 
and  represent  the  relationship  of  families  as  we  find  them. 

y.  As  affecting  Generic  Characters. 

If  the  extremes  of  our  series  of  genera  were  characterized  by 
structures  particularly  adapting  them  above  all  others  to  some 
contemporary  necessity  of  existence,  this  second  law,  or  Darwin's, 
might  be  regarded  as  primary.  But  the  writer's  experience  of 
comparative  anatomy  has  led  him  to  believe  that  this  is  not  the 
case,  as  expressed  in  Proposition  IV,  page  91. 

This  view  had  not  been  overlooked  by  Darwin,  who,  however, 
treats  of  it  very  briefly,  and  appears  to  attach  it  to  the  theory 
of  adaptations,  or  modifications  for  a  physiological  purpose.  He 
says,  ^^  Origin  of  Species,"  page  388  (Amer.  edit.,  1860)  :  "We 
may  extend  this  view  to  whole  families,  or  even  classes.  The 
fore-limbs,  which  served  as  legs  in  the  parent  species,  may  become, 
by  a  long  course  of  modification,  adapted  in  one  descendant  to 
act  as  hands,  in  another  as  paddles,  in  another  as  wings ;  and  on 
the  above  two  principles— namely,  of  each  successive  modification 
supervening  at  a  rather  later  age,  and  being  inherited  at  a  corre- 
spondingly late  age— the  fore-limbs  in  the  embryos  of  the  several 
descendants  of  the  parent  species  will  still  resemble  each  other 
closely,  for  they  will  not  have  been  modified.  But  in  each  indi- 
vidual new  species  the  embryonic  fore-limbs  will  differ  greatly 
from  the  fore-limbs  in  the  mature  animal ;  the  limbs  in  the  latter 
have  undergone  much  modification  at  a  rather  late  period  of  life, 


108  GEi^ERAL  EYOLUTION. 

and  having  thus  been  converted  into  hands,  paddles,  or  wings." 
He  then  inclines  to  assign  this  change  to  the  necessity  of  external 
circumstance.  But  such  modification  must  be  the  same  in  kind 
as  others,  which  the  same  hypothesis  must  explain,  and  of  which 
the  same  author  remarks  (page  882)  :  ''  We  can  not,  for  instance, 
suppose  that  in  the  embryos  of  the  Vertebrata  the  peculiar  loop- 
like course  of  the  arteries  near  the  branchial  slits  are  related 
to  similar  conditions  in  the  young  mammal,  which  is  nourished 
in  the  womb  of  its  mother,  in  the  egg  of  the  bird  which 
is  hatched  in  a  nest,  and  in  the  spawn  of  a  frog  under  water.  We 
have  no  more  reason  to  believe  in  such  a  relation  than  we  have  to 
believe  that  the  same  bones  in  the  hand  of  a  man,  wing  of  a  bat, 
and  fin  of  a  porpoise,  are  related  to  similar  conditions  of  life. 
'No  one  will  suppose  that  the  stripes  on  the  whelp  of  the  lion,  or 
the  spots  on  the  young  blackbird,  are  of  any  use  to  these  animals, 
or  related  to  the  conditions  to  which  they  are  exposed." 

The  law  of  natural  selection,  however,  has  no  doubt  been  a 
very  important  agency  in  the  production  of  organic  types  in  dif- 
ferent periods  of  the  world's  history  ;  but  the  part  it  has  played  in 
the  determination  of  generic  features  would  appear  to  have  been 
very  small. 

In  its  first  effect — that  of  producing  a  structure  adapted  for 
a  particular  purpose — it  would  seem  to  have  acted  differently  to 
produce  the  same  results,  and  hence  not  to  have  produced  any  of 
the  more  extended  groups,  as  families,  where  hundreds  of  species 
are  identical  in  a  single  feature.  Witness  the  differences  in  di- 
verse types  of  the  tree-frogs,  each  type  adapting  its  possessor  to 
an  aboreal  life  : 

I.  Claw-like,  with  globular  base Hylid^. 

Leptopelis. 
II.  Simple,  obtuse-depressed  at  tip Ranid^.  I  aa  and  III  a. 

III.  With  a  terminal  transverse  limb Ranid^,  Hylarana  et  aff. 

Callula. 

Brachymerus. 

Hi/lodes. 

IV.  Bifurcate Bcitrachyla. 

Dendrohates. 

Polypedates. 

RhacopJioms. 

The  short  foot  of  the  Testudinid?e,  where  one  row  of  pha- 
langes is  omitted,  has  been  already  alluded  to.  The  gradual  re- 
duction of  this  set  of  bones,  accompanying  general  modification 
of  form  in  the  increased  convexity  of  dorsal  region,  as  Ave  leave  the 
more  aquatic  and  progress  toward  the  terrestrial  tortoises,  would 


ON  THE  ORIGIN  OF  GENERA.  109 

seem  to  be  intimately  connected  with  difference  of  habit.  The 
increased  convexity  of  carapace  is  an  increased  defense  from  fall- 
ing objects — a  danger  to  which  land  tortoises  are  far  more  subject 
than  the  aquatic.  Another  protection,  not  needed  by  water  tor- 
toises so  much  as  by  terrestrial,  is  the  faculty  of  closing  one  or 
both  free  lobes  of  the  plastron,  as  seen  in  the  Cistudo,  Sternothse- 
rus,  etc.,  or  of  portions  of  the  carapace,  as  in  Pixys,  Cinixys,  etc. 
This  might  really  have  been  produced  by  excessive  tension  on  the 
sternal  and  pelvic  muscles  while  young,  and  while  the  sutures 
were  not  fully  interlocked.  This,  continued  for  a  long  time, 
might  have  produced  the  result.  Yet  it  is  not  easy  to  see  what 
protection  the  aquatic  Kinosterna  need  in  this  respect,  above  the 
Emydes  of  the  same  countries.  The  backs  of  these  genera  are 
also  as  convex  as  are  many  of  the  terrestrial  genera  or  Testu- 
dinidse. 

I  can  not  better  express  my  views  than  by  quoting  the  follow- 
ing from  the  pen  of  the  late  Dr.  Falconer.  It  is  extracted  from 
one  of  his  essays  on  the  Elephantidae  :  * 

'^  Each  instance,  however  different  from  another,  can  be  shown 
to  be  a  term  of  some  series  of  continued  fractions.  When  this  is 
coupled  with  the  geometrical  law  governing  the  evolution  of  form, 
so  manifest  in  shells  of  the  Mollusca,  it  is  difficult  to  believe  that 
there  is  not  in  nature  a  deeper-seated  and  innate  princij^le,  to  the 
operation  of  which  natural  selection  is  merely  an  adjunct. 

**  The  whole  range  of  the  Mammalia,  fossil  and  recent,  can 
not  furnish  a  species  which  has  had  a  wider  geograjDhical  distri- 
bution, and  at  the  same  time  passed  through  a  longer  term  of 
time,  and  through  more  extreme  changes  of  climatal  conditions 
than  the  mammoth. 

*'If  species  are  so  unstable  and  so  susceptible  of  mutation 
through  such  influences,  why  does  that  extinct  form  stand  out  so 
signally  a  monument  of  stability  ?  By  his  admirable  researches 
and  earnest  writings,  Darwin  has,  beyond  all  his  contemporaries, 
given  an  impulse  to  the  philosophical  investigation  of  the  most 
backward  and  obscure  branch  of  the  biological  sciences  of  the 
day  ;  he  has  laid  the  foundation  of  a  great  edifice  ;  but  he  need 
not  be  surprised  if,  in  the  progress  of  erection,  the  superstructure 
is  altered  by  his  successors,  like  the  Duomo  of  Milan,  from  the 
Roman  to  a  different  style  of  architecture. 


*  See  writings  of  Hugh  Falconer,  vol.  ii  (ed.  by  Murchison). 


110  GENERAL  EVOLUTION. 

''  The  inferences  which  I  draw  from  these  facts  are  not  op- 
posed to  one  of  the  leading  propositions  of  Darwin's  theory. 

*^  With  him  I  have  no  faith  in  the  opinion  that  the  mammoth 
and  other  extinct  elephants  made  their  appearance  suddenly,  after 
the  type  in  which  their  fossil  remains  are  pre:ented  to  us.  The 
most  rational  view  seems  to  be,  that  they  are  in  some  shape 
the  modified  descendants  of  earlier  progenitors.  Eut  if  the  as- 
serted facts  be  correct,  they  seem  clearly  to  indicate  that  the  older 
elephants  of  Europe,  such  as  U.  meridionalis  and  E.  antiqmis, 
were  not  the  stocks  from  which  the  later  species,  E.  primigenius 
and  E.  africanus  sprung,  and  that  we  must  look  elsewhere  for 
their  origin.  The  nearest  affinity,  and  that  a  very  close  one,  of 
the  European  E.  mericlio7ialis,  is  with  the  Miocene  E.  (Loxod.) 
planifrons  of  India,  and  of  E.  primige?iius  with  the  existing  In- 
dian species. 

*^  Another  reflection  is  equally  strong  in  my  mind,  that  the 
[theories  of  the  origin  of]  species  by  ^  natural  selection,'  or  a  pro- 
cess of  variation  from  external  influences,  are  inadequate  to  ac- 
count for  the  phenomena.  The  law  of  Phyllotaxis,  which  gov- 
erns the  evolution  of  leaves  around  the  axis  of  a  plant,  is  nearly 
as  constant  in  its  manifestation  as  any  of  the  physical  laws  con- 
nected with  the  material  world." 

6.  Js  affectiiig  Specific  Characters. 

As  I  have  hitherto  attempted  to  prove  that  the  higher  grade 
of  groups,  or,  in  other  words,  the  higher  grade  of  characters, 
could  not  have  had  their  origin  through  natural  selection  alone, 
though  admitting  it  as  a  conserving  or  restricting  principle,  I 
now  come  to  ground  where  natural  selection  must  be  allowed  full 
sway.  The  "  origin  of  species  "  is  not  the  object  of  this  essay,  as 
a  greater  has  gone  before  me,  and  has  done  a  great  deal  toward 
showing  that  a  selective  power,  deiDcndent  on  adaptation  and  tele- 
ological  relation,  has  favored  or  repressed,  or  even  called  into  ex- 
istence, the  varied  peculiarities  that  characterize  species  and  races. 
I  will  therefore  only  refer  to  his  well-known  works  on  the  ^^  Origin 
of  Species  "  and  the  ^'  Modifications  of  Animals  under  Domestica- 
tion." 

I  may  add  that  it  is  within  the  range  of  possibility  that  that 
grade  or  kind  of  characters  found  to  define  i\iQ  family  group  may 
be  more  or  less  the  result  of  natural  selection. 

Acceleration  and  retardation  are  also  far  from  excluded  from 


ON  THE   ORIGIN   OF  GENERA.  m 

the  probable  causes  of  specific  characters.  The  species  of  many 
genera  do  exhibit  a  proportion  of  characters  which  are  the  succes- 
sive stages  of  that  one  which  progresses  farthest,  as  the  species  of 
Amblystoma  in  the  position  of  their  teeth,  nostrils,  form  of  tail, 
and  coloration  ;  of  Hyla  in  form  of  vomerine  teeth,  etc.  But  the 
majority  of  specific  characters  are  of  divergent  origin — are  'Amor- 
phic "  as  distinguished  from  developmental. 

e.    On  Metaphysical  Species. 

One  of  the  arguments  employed  against  the  developmental 
hypothesis,  in  any  form,  is  that  that  inherent  "potentiality," 
which  causes  that  like  shall  always  produce  like,  is  a  metaphysi- 
cal being,  which  can  not  be  transformed,  and  which  holds  the 
structure  which  it  vivifies  as  a  material  expression  or  stamp  of  it- 
self, and  which  therefore  can  not  be  changed. 

One  expression  of  this  inherent  metaj^hysical  specific  individu- 
ality, if  the  term  may  be  allowed,  has  been  said  to  be  the  peculiar 
traits  of  the  intelligence  of  species,  their  motions,  voices,  and  in- 
stincts. But  intelligence  of  all  animals  is  susceptible  of  impres- 
sions, the  lower  the  intelligence  the  less  susceptible,  and  the  more 
automatic.  But,  as  we  rise  in  the  scale  of  animal  being,  this  im- 
pressibility and  capacity  for  education  is  undeniably  exhibited  by 
the  dog,  horse,  and  all  the  well-known  domesticated  companions 
of  man.  There  can,  in  view  of  the  capacities  of  Aves  and  Mam- 
malia in  these  respects,  be  little  doubt  that  all  animals  are  edu- 
cated by  the  *'  logic  of  events,"  that  their  intelligence,  impressed 
by  changed  circumstances,  can  accommodate  itself  more  or  less  to 
them,  and  that  there  is  nothing  in  this  part  of  their  being  opposed 
to  the  principle  of  "descent  with  modification." 

There  is  another  difficulty  in  the  way  of  accepting  metaphys- 
ical peculiarity  or  progenitiveness  as  isolating  species.  It  is 
marked  often  strongly  in  races  or  varieties,  which  no  one  pre- 
tends to  have  had  distinct  origin.  Here  like  produces  like  con- 
tinually, though  not  persistently,  but  sufficiently  to  show  that  it 
resides  in  varieties  of  common  origin.  The  isolation  of  allied 
species  in  fact  depends,  I  believe,  solely  on  the  supremacy  of  the 
automatic  over  the  intelligent  spirit.  When  the  intelligent  rises 
above  the  bounds  of  nature,  or  the  automatic,  the  mixture  or 
separation  of  allied  species  depends  merely  on  circumstances  of 
necessity,  determined  by  that  intelligence. 

But  the  metaphysical  ''  potentiality  "  loses  all  basis,  if  the  law 


112  GENERAL  EVOLUTION. 

of  acceleration  and  retardation  be  true,  for  in  accordance  with  it, 
at  certain  times,  like  does  not  produce  like, 

V.    OF   EPOCHAL   EELATIOI^S,    OR  THOSE   MEASURI2^G   GEOLOGIC 

TIME. 

If  it  can  be  shown  that  groups  haying  the  develo2)mental  rela- 
tion above  insisted  on  are  contemporaries,  and  if  it  can  be  shown 
that  this  relation  is  identical  in  kind  with  that  which  we  regard 
as  measuring  the  successions  of  geologic  time,  we  will  be  led  to 
doubt  the  existence  of  any  very  great  interruptions  in  the  course 
of  this  succession  throughout  geologic  time.  And  if  we  can  show 
that  faunae  so  related  are  more  or  less  characteristic  of  distinct  por- 
tions of  the  earth's  surface,  at  the  present  time,  we  will  be  led  to 
antici23ate  that  contemporaneous  faunge  in  different  regions,  during 
geologic  periods  also,  bore  such  a  relation.  If  this  proposition  be 
true,  we  are  led  to  the  further  conclusion,  which  is  at  variance 
with  received  canons,  that  identity  of  faunae  proves  successional 
relation  in  time,  instead  of  synchronism.*  That  this  will  ulti- 
mately be  demonstrated  appears  highly  probable  to  the  writer, 
though,  as  yet,  the  evidence  is  but  fragmentary. 

If  the  relations  expressed  under  the  terms  homology  and  het- 
erology, taken  together  with  the  observations  on  metamorphosis, 
render  it  j^robable  that  a  number  of  genera  have  reached  their  ex- 
pression-points, or  periods  of  metamorphosis,  at  near  the  same 
time  in  geologic  history,  an  important  point  has  been  gained. 
If  we  can  render  it  probable  that  a  change  in  any  organic  charac- 
ter has  been  nearly  simultaneous  throughout  a  large  extent  of 
specific  forms,  the  change  becomes,  on  the  latter  account  alone, 
of  higher  than  generic  value,  but  characteristic  of  such  groups  as 
Marsupialia,  Clamatores,  Acrodonta,  Arcifera,  Heterocerca,  and 
the  like. 

We  have  here,  also,  an  important  element  in  the  estimation  of 
the  value  of  apj^arent  interruptions  in  the  geological  history  of 
the  life  of  the  globe.  These  interruptions,  it  is  true,  are  greater 
than  any  such  theory  as  the  present  can  bridge  over ;  yet  such  a 
theory,  if  true,  lessens  their  importance.  They  are  in  any  case 
well  accounted  for  on  the  theory  of  the  existence  of  periods  of 
elevation,  during  which  the  life  of  a  given  region  is  necessarily 
almost  entirely  lost  to  us,  through  lack  of  means  of  preservation 
of  their  remains. 

*  This,  view  has  been  insisted  on  by  Huxley. 


ON"  THE   ORIGIN   OF   GENERA.  113 

We  may  also  compare  such  extended  metamorphoses  with 
those  of  cosmical  matter,  such  as  when,  in  the  course  of  ages,  a 
primeval  vapor  has  in  a  short  time  collapsed  to  the  liquid  form,  or 
as  when  the  vast  of  liquid  in  turn  has  shrunk  to  its  solid  con- 
dition ;  both  alike  for  ages  approaching  their  change,  yet  sta- 
tionary in  external  relations  till  the  moment  of  transition  has 
arrived. 

The  following  are  the  zoological  relations  of  the  groups  al- 
ready referred  to  : 

The  most  generalized  group  of  fishes  of  the  Regio  Neotropica 
is  that  of  Characins.  Its  type,  in  respect  to  fin-structure,  which 
is  common  to  all  the  Malacopterygians,  is  that  of  an  undeveloped 
stage  of  the  Acanthopterygians,  the  adipose  fin  being  an  undevel- 
oped cartilaginous  fin,  and  the  cartilaginous  fin  an  undeveloped 
spinous  fin.*  It  may  be  said  to  be  the  highest  among  Malacop- 
terygians, if  we  look  to  the  conq^lete  oviducts,  opercula,  jaws,  etc.,t 
but  it  is  the  lowest  as  removed  farthest  from  the  extreme  of 
Malacopterygian  peculiarities,  as  being  most  generalized  or  em- 
bracing representatives  of  all  the  rest,  and  approaching  nearest 
the  types  of  the  past — the  Ganoids.  Tor  example,  Butyrinus  and 
Vastres  may  be  compared  with  Amia.  The  family  is  distributed 
chiefly  in  the  Southern  Hemisphere. 

The  genus  Orestias,  which  Agassiz  says  is  characterized  by  a 
feature  which  exists  in  the  immature  state  of  all  other  Oyprino- 
donts — the  absence  of  ventral  fins — is  only  found  in  the  Neotrop- 
ical region. 

Of  the  yenomous  serpents,  the  inferior  group,  the  Proterogly- 
pha,  belong  to  the  Southern  Hemisphere,  and  the  Australian  and 
Neotropical  regions  almost  exclusively  embrace  by  far  the  greater 
proportion.     Australia  contains  none  other. 

The  Iguanian  lizards  are  lower  than  the  Acrodont,  exhibiting 
a  larval  type  of  detention,  and  one  characteristic  of  all  lower  Sau- 
ria  and  Batrachia.  The  only  acrodont  type  of  Ophiosaura  (Trog- 
onophis)  is  Old  World. 

The  New  World  Teidas  have  not  the  extent  of  ossified  tem- 
poral roof  that  their  representatives,  the  Old  World  Lacertidae, 
have.     So  the  chiefly  Neotropical  Anguidae  haye  the  tongue  part- 


*  Kner,  "  Ueber  den  Bau  der  Flosscn." 

\  This  is  the  correct  view,  for  this  family  and  the  Siluroids  are  the  most  special- 
ized  of  the  Malacopterygian  fishes.     (1886.) 
8 


114  GENERxiL  EVOLUTIOK 

ly  of  papillose  type  of  tlieir  Old  World  representatives,  the  Zonu- 
ridae,  and  partly  the  smooth  or  scaly  type  of  the  cosmopolite  Scin- 
cidse,  which  are  inferior  to  them. 

The  snake-like  forms  of  the  families  of  the  Lacertilia  Lepto- 
glossa  greatly  predominate  in  the  Southern  Hemisphere  ;  also 
those  with  undeveloped  palj^ebrae. 

The  Neotropical  type  of  Testudinata  is  quite  coincident  with 
the  family  Characinidae  in  relations.  It  is,  like  it,  largely  dis- 
tributed over  the  Southern  Hemisphere,  and  like  it  may  be  re- 
garded, in  respect  to  its  pelvic  peculiarities,  as  higher  than  the 
remaining  types,  but  in  its  generalized  character  and  relationship 
to  the  past  periods  may  be  called  lower. 

The  Neotropical  type  of  Batrachia  anura,  that  is,  the  Arcifera, 
is  lower  in  developmental  characters  than  the  opposed  series,  the 
Eaniformia  ;  such  of  the  latter  as  are  found  in  its  limits  partake 
in  some  way  of  larval  incomjileteness.  The  Arcifera  are  chiefly 
distributed  elsewhere  in  Australia,  where  no  Eaniformia  exist.* 
Those  genera  of  Old  World  Eaniformia  of  the  lowest  or  toothless 
group,  which  display  the  least  development  of  the  cranial  bones, 
as  Brachymerus  and  Breviceps,  are  of  the  Southern  Hemisphere — 
South  African. 

The  Pullastrine  birds  are  a  generalized  group,  inferior  to  the 
group  opposed  to  them — the  Gallinae.  Their  typical  forms,  like 
the  last,  are  distributed  to  the  Neotropical  and  Australian  regions : 
the  outliers  (pigeons)  are  not  so  numerously  distributed  in  the 
other  regions. 

The  Struthious  birds,  the  most  synthetic  of  the  class,  belong 
exclusively  to  the  Southern  Hemisphere  ;  as  is  well  known,  they 
chiefly  abound  in  Australia  and  its  adjacent  islands,  with  an  abun- 
dant outlying  type — the  Tinamus — in  South  America. 

The  penguins,  which  only  of  all  birds  display  the  metatarsus 
nearly  divided,  inhabit  the  Antarctic  regions  and  Cape  Horn. 

*  The  Eucnemis  bicolor,  Gray,  would  appear  to  be  an  exception,  were  its  generic 
and  subordinate  affinities  truly  represented  by  its  name.  I  have  examined  the  type 
specimen  through  the  kindness  of  Dr.  Giinther,  and  can  state  that  it  is  not  an  Ixa- 
lus  {=  Eucnemis),  and  does  not  even  belong  to  the  Eaniformia,  but  is  an  Arcifer  of 
the  family  HyUdae.  If  it  be  not  a  young  Calamita  or  Hyla,  it  will  be  a  Hylella  near 
the  K  carnea  type.  (Boulenger,  in  1882,  determined  it  to  be  a  Hylella.  Ed. 
1886.) 

Giinther  states  that  Hylorana  erpthraea  has  been  found  at  the  extreme  northern 
point — Cape  York — of  Australia.  If  so,  the  case  is  parallel  to  the  occurrences  of 
the  Raniform  Ranula  in  northern  South  America. 


ON   THE   ORIGIN   OF   GENERA.  II5 

The  Clamatorial  type  of  the  Passeres  exhibit  larval  characters 
in  the  non-development  of  the  singing  apparatus,  and  the  scaled 
or  nearly  naked  tarso-metatarsus.  These  are  chiefly  South  Amer- 
ican. 

Of  Mammalia,  the  placentals  without  enamel  on  their  teeth, 
which,  in  this  respect,  never  reach  the  full  development  of  the 
class,  whose  dentition  is  also  monophyodont,  i.  e.,  the  Edentata, 
inhabit  only  the  Southern  Hemisphere,  and  almost  altogether  the 
Neotropical  region.  The  implacental  Mammalia,  also  (except  in 
one  tooth)  monophyodont,  which  approach  birds  and  reptiles  in 
so  many  respects,  are  confined  to  the  Southern  Hemisphere,  and 
chiefly,  as  all  know,  to  Australia. 

Of  the  Quadrumana,  the  Platyrrhine  group  is  known  to  be  in- 
ferior to  the  Catarrhines  :  the  former  presents  an  entirely  embry- 
onic condition  of  the  os  tympa7iicum,  which  is  passed  by  the  latter 
in  early  age  ;  *  it  contains  also  the  only  clawed  genus  of  the  true 
monkeys.  It  is  confined  to  the  Neotropical  realm.  To  Madagascar, 
also  of  the  Southern  Hemisphere,  and  nearest  in  many  ways  to 
the  Neotropical,  pertain  the  lowest  families  of  the  Quadrumana, 
the  Lemuridae  and  Chiromyidas  ;  the  former  presenting  brains 
without  convolutions,  and  approaching  in  many  ways  the  Insec- 
tivora  ;  the  last  imitating,  at  least,  a  Eodent. 

There  are  also  other  reasons  for  the  inferiority  of  South  Amer- 
ica. Its  deer,  which  are  few,  include  those  which  never  produce 
more  than  the  ^^dague,"  or  the  first  horn  of  the  northern  Cervus, 
and  also  those  which  never  get  beyond  the  fourth  step  in  the  de- 
velopment of  the  lower  group  of  R.  Nearctica. 

The  Loricariidae,  of  South  America,  I  am  informed  by  Prof. 
Agassiz,  possess  the  foetal  pupil  of  the  vertebrate  type. 

If  we  glance  at  Coleoptera  we  find  the  great  predominance  of 
the  groups  with  undeveloped  tarsus,  the  three-  and  four-jointed 
Trimera  and  Tetramera,  and  of  the  lower  group  with  undeveloped 
sternum,  f  the  Rynchophora,  in  the  Neotropical  region. 

Among  Lepidoptera  it  is  known  that  the  most  gigantic  of  the 
species  of  the  Neotropical  region  are  Noctuidae  (Erebus,  etc. ),  and 
that  in  that  region  this  low  type  of  the  order  reaches  its  greatest 
development.  The  largest  forms  of  the  Regio  Nearctica,  as  well 
as  Pal^arctica,  are  representatives  of  the  higher  type  of  the  Satur- 


*  See  Dr.  H.  Allen,  "Proceed.  A.  N.  S.,"  Phila.,  186Y. 
\  Leconte,  American  Association,  1867. 


116  GENERAL  EVOLUTION. 

niidse  (Atticus,  Telea,  etc.),  while  the  largest  and  most  powerful 
of  this  order  in  the  Palaeo tropical  (Indian)  region  are  the  Papilio- 
nid  forms  of  Ornithoptera,  etc.,  the  generally  admitted  crown  and 
head  of  all.  Of  course  other  types,  both  higher  and  lower,  are 
largely  developed  in  each  and  all  of  these  regions,  and  the  signifi- 
cance of  the  aboye  facts  is  perhaps  only  to  be  seen  when  taken  in 
connection  with  a  large  number  of  others  pointing  in  the  same 
direction. 

Two  or  three  comparisons  of  different  faunae  may  be  brought 
forward  finally.  First,  returning  to  the  birds,  a  survey  of  some 
of  the  differences  between  the  birds  of  Panama,  Pennsylvania,  and 
Palestine  may  be  made.* 

Tristram  noticed  three  hundred  and  twenty-two  species  of 
birds  within  the  range  of  the  ancient  territory  of  Palestine.  Of 
these  two  hundred  and  thirty  were  land  and  ninety-two  water 
birds,  i.  e.,  Natatores  and  the  wading  Cursores.  Of  the  two  hun- 
dred and  thirty,  seventy-nine  are  common  to  the  British  Islands, 
and  thirty-six  of  them  are  found  in  China,  but  a  small  j^roportion 
extending  their  range  to  both  these  extremes.  Of  the  water  birds, 
which  are  always  more  widely  distributed,  fifty-five  of  the  ninety- 
two  are  British  and  fifty-seven  Chinese.  Twenty-seven  appear  to 
be  confined  to  Palestine,  and  to  the  immediately  adjacent  country  ; 
the  largest  of  these  is  a  crow. 

Taking  the  two  hundred  and  thirty  land  birds  at  a  glance, 
we  find  the  utter  absence  of  so  many  of  the  well-known  forms 
that  enliven  our  grounds  and  forests.  The  absence  of  Tanagridse 
(including  Sylvicolidae)  and  Icteridse,  changes  the  aspect  of  the 
bird-fauna  at  once.  What  have  we  here,  then,  of  nine-quilled 
Oscines  to  enliven  the  meadows  like  our  swarms  of  blackbirds,  or 
fill  the  tree-tops  and  thickets  with  flutter  like  our  wood-warblers  ? 
Nothing  ;  for  the  twenty-four  species  of  finches,  Fringillidae,  will 
but  balance  our  own,  though  the  genera  are  all  different  but  four, 
and  they  the  most  weakly  represented  by  species.  We  must  look 
to  the  higher  series,  the  ten- quilled  song-birds,  for  the  missing 
rank  and  file.  While  a  much  larger  extent  of  the  Eastern  United 
States  possesses  fifty  species  of  these  types,  the  little  Palestine  has 
already  furnished  a  list  of  one  hundred  and  twenty-eight. 

First,  of  the  crows,  which  verge  nearest  Icteridae  hj  the  star- 
lings, we  have  thirteen  species  against  five  in  our  district  of  the 

*  From  the  "American  Naturalist,"  1868,  by  the  author. 


ON"  THE   ORIGIN   OF   GENERA.  ^^^ 

United  States,  and  not  less  than  seven  of  the  typo  genus  Corvus 
to  our  one  common  and  two  rare.  Of  these  two  are  of  the  laro-er 
species,  the  ravens.  If  we  turn  to  the  cheerful  larks,  we  find  the 
proportion  again  the  same  ;  fifteen  species  for  Palestine  and  one 
for  the  whole  United  States.  One  congener  of  our  species  occurs 
there  ;  the  other  genera  call  to  mind  the  African  deserts  and  Rus- 
sian steppes.  Motacillidse,  again,  ten  to  one  against  our  fauna.  We 
have  two  Tanagridae  to  imitate  them,  besides  the  one  true  relative. 
In  swallows  we  are  about  equal,  and  in  the  forest-haunting  Parid^ 
— titmice  and  wrens — we  exceed  a  little  ;  but  the  comparison  of 
Sylviidse  and  Turdidas  is  most  striking.  These  highest  of  the  bird 
series,  especially  made  to  gladden  man's  haunts  with  song,  exceed 
in  number  all  the  other  ten-quilled  Oscines  together  inhabiting 
Palestine,  amounting  to  seventy-five  species.  In  our  correspond- 
ing region  of  the  United  States  nineteen  species  is  the  quantum. 
It  is  true  no  mocking-bird  or  wood-robin  is  known  away  from  our 
shores,  but  Palestine  has  the  nightingale,  the  black-cap,  and  the 
true  warblers  or  sylvias,  which,  while  they  glean  from  shrub  and 
tree  their  smallest  insect  enemies,  as  do  our  equally  numerous 
small  Tanagridse,  have  much  louder  and  sweeter  voices. 

Our  solitary  bluebird  represents  the  long-winged  Turdidae  ;  in 
the  Holy  Land  there  are  twenty  species  corresponding,  though 
none  are  of  our  genus.  There  are,  indeed,  but  three  genera  of 
these  two  families  common  to  both  countries.  One  of  these,  La- 
nius,  the  butcher-bird,  occurs  here  in  one  species,  in  Palestine 
in  six. 

Turning  now  to  a  lower  series,  we  look  in  vain  for  Clamatorial 
perchers  ;  that  series  which  gives  us  the  fierce  king-bird  and  queru- 
lous pewee,  and  which  peoples  South  America  with  thrush  and 
warbler,  and  shrike  and  tree-creeper. 

In  taking  a  hasty  glance  over  the  lower  groups,  where  the  carot- 
id arteries  begin  to  be  double,  as  the  Syndactyli,  we  find  Palestine 
too  far  from  the  tropics  to  present  us  with  much  array ;  but  in 
the  related  zygodactyles  our  forest-crowned  continent  must  claim 
great  pre-eminence.  It  has  but  a  solitary  Picus,  while  we  have 
eight  in  the  immediate  neighborhood  of  lat.  40°,  in  our  Eastern 
States. 

I  will  close  with  the  birds  of  prey.  Four  swamp-hawks,  eleven 
species  of  falcons,  four  kites,  and  eight  native  eagles,  form  a  list 
unequaled  in  the  annals  of  nobility  by  any  land.  There  are  to- 
gether thirty-one  species  of  Falconidae,  and  of  Vultures  four.    The 


118  GENEKAL  EVOLUTION. 

eagles  appear  to  be  all  common,  among  them  the  most  magnificent 
birds  of  prey,  the  imperial  and  golden  species  of  these  creatures. 

To  the  ornithologist,  acquainted  with  the  fauna  of  North 
America,  it  will  thus  be  readily  perceived  that,  in  comparison,  the 
ornis  just  examined,  possesses  more  numerous  representatives  of 
the  higher  groups  of  the  birds,  and  among  lower  groups  possesses 
chiefly  those  of  superior  grade,  or  lacks  them  altogether.  Let  us, 
however,  compare  it  with  that  of  Central  America,  where  varied 
surface  and  temperature  offer  even  greater  opportunity  for  variety, 
within  quite  as  restricted  an  area. 

The  bird  fauna  has  been  found  by  Messrs.  Sclater  and  Salvia 
to  embrace  about  three  hundred  and  eighty-five  species,  which  is 
sixty-three  more  than  were  mentioned  to  occur  in  Palestine,  which 
is  open  on  three  sides  to  the  great  continent.  Eighty  of  three 
hundred  and  forty-eight  land  birds  are  characteristic  of  Central 
America  ;  and  those  which  find  their  kin  limited  to  the  Isthmus 
and  adjoining  regions  of  New  Grenada  and  Equador  amount  to 
about  seventy-five  more.  Twenty-seven  is  the  number  not  known 
to  extend  beyond  the  boundaries  of  Palestine  ;  as  to  the  Middle 
States  of  our  Union,  not  one  species  has  been  shown  to  be  restricted 
within  such  narrow  limits. 

A  single  species  occurs  in  Europe ;  this  is  the  fish-hawk,  an 
animal  which  combines  the  cosmopolite  habit  of  the  sea-bird  with 
the  powerful  flight  of  the  bird  of  prey.  This  is  also  the  only  sj^e- 
cies  common  to  the  Panama  and  Palestine  catalogues. 

The  birds  of  prey  are  numerous — twenty-nine  species.  Among 
these  there  is  no  true  eagle  or  falcon,  and  of  the  nineteen  genera 
but  four  belong  to  the  fauna  of  the  Holy  Land.  There  is  but  one 
species  to  represent  the  great  grouse  family,  but,  instead,  three 
families  of  their  South  American  imitators,  the  Pullastrse,  instead 
of  the  one — that  of  the  Pigeons — slimly  represented  in  Palestine, 
and  in  North  America  as  well. 

Coming  to  the  closer  test  of  superiority,  the  Passeres — those 
delicate  creatures,  apparently  so  dependent  on  those  laws  which 
govern  increase  and  provision,  and  so  affected  by  the  changes  that 
man  works  in  the  face  of  Nature — what  do  we  find  ?  We  count 
one  hundred  and  six  distinct  species.  There  are  none  in  Pales- 
tine. Of  songsters,  the  Oscines,  ninety-six  species,  await  man's 
conquest  of  the  wilderness,  to  increase  in  numbers  and  to  display 
their  gifts,  while  Palestine  rejoices  in  a  whole  army  of  them.  But 
the  contrast  is  more  remarkable  if  we  analyze  these  forms.    Of  the 


ON  THE  GRIGIN   OF  GENERA.  119 

Isthmian  Oscines,  seventeen  only  hold  the  first  rank,  by  virtue  of 
their  additional,  the  tenth  primary  quill,  while  this  feature  marks 
one  hundred  and  twenty-eight  species  of  Palestine.  As  we  rapidly 
follow  the  line  to  the  point  where  its  extreme  is  manifested,  in  the 
family  of  the  Thrushes  or  Turdidae,  Panama  is  left  but  two  soli- 
tary pioneers  of  these  songsters  of  the  North,  while  seventy-five 
species  represent  the  family  in  Palestine. 

The  comparison  between  different  faunae  exhibits  an  apparent 
gradation  in  some  other  groups  equally  curious.  Thus,  the  true 
Cyprinidae  in  the  Palaearctic  region  reach  a  great  development, 
and  produce  the  highest  number  of  teeth  on  their  pharyngeal  jaws 
known,  as  well  as  attains  the  greatest  bulk  and  importance.  The 
number  of  these  teeth  is  usually  seven  to  five  in  the  inner  row ; 
only  two  or  three  genera  exhibit  only  four  on  both.  In  the  Ne- 
arctic  region  the  number  of  teeth  is  almost  always  4 — 4,  more 
rarely  4 — 5,  and  very  seldom  as  high  as  5 — 5.  The  species  of  the 
family  are  excessively  numerous,  but  are,  with  scarcely  any  excep- 
tion, of  small  size  and  weak  organism.  These  statements  apply  to 
those  of  the  eastern  district  of  the  region  between  the  Rocky 
Mountains  and  the  Atlantic.  Similar  types  occur  in  the  northern 
region  of  the  Neotropical — Mexico,  but  in  no  great  numbers. 
Farther  south  the  family  disappears,  its  place  being  sujoplied  by 
the  generalized  family  of  Characinidae. 

I  have  already  alluded  to  the  great  variety  of  the  highest  or 
pentamerous  carnivorous  beetles  in  the  Palaearctic  region.  They 
are  extremely  abundant  in  the  Nearctic,  while  the  intermediate 
territory,  the  Sonoran  and  Mexican  sub-districts,  are  the  head- 
quarters of  the  next  lower  form,  the  Tenebrionidae,  which  have 
the  tarsal  joints  4 — 5.  These  give  place  in  the  Neotropical  to  the 
multitudes  of  the  still  lower  series — those  with  the  joints  4 — 4  and 
3 — 3 — Tetramera  and  Trimera. 

The  preceding  comparisons  indicate  that  an  inherent  difference 
between  the  types  of  a  continent  exists  at  the  present  time,  tliough 
the  difference  is  subordinated  to  a  universal  distribution  of  the 
higher  groups  throughout  the  earth.  Has  this  state  of  things  ex- 
isted for  any  long  period,  or  is  it  a  result  of  different  progress  in 
the  same  group  since  the  human  period  ?  This  brings  us  neces- 
sarily to  a  consideration  of  the  truths  of  paleontology,  especially 
of  the  last  periods,  which  have  been  already  urged  by  Darwin. 
Thus  the  present  fauna  of  Australia  was  preceded  in  the  Post-Pli- 
ocene and  Pliocene  by  forms  possessing  similar  peculiarities,  and 


120  GENERAL  EVOLUTION. 

belonging  to  the  same  classes.  That  is  by  herbivorous  and  car- 
nivorous marsupials  and  monotremes,  and  by  Varanid  Sauria,  all 
of  greater  size  than  their  predecessors. 

The  same  fact  is  well  known  of  the  Neotropical  region,  its 
present  peculiar  Edentata  having  been  preceded  by  giants  of  the 
same  type  in  the  Post- Pliocene  and  Pliocene. 

In  the  Nearctic  region  peculiar  existing  genera,  as  Procyon, 
Alces,  Castor,  Bos,  Sciurus,  Arctomys,  Lepus,  Ovibos,  Sorex,  Me- 
phitis, Felis,  Ursus,  Menopoma,  Aspidonectes,  Orotalus,  are  rep- 
resented by  Post-Pliocene  fossils. 

The  same  occurs  in  the  later  Palsearctic  formations,  where  Cer- 
vus.  Bos,  Canis,  Mustelidse,  Insectivora,  Vipera,  Alytes,  Triton, 
etc.,  are  allied  predecessors  of  existing  types.  In  the  Palseotrop- 
ical  area  a  wonderful  development  of  Elephas  and  Gavialis  preceded 
the  same  types  of  the  present. 

Prior  to  these  faunas  another  state  of  things  has,  however,  ex- 
isted. North  America  has  witnessed  a  withdrawal  of  a  Neotrop- 
ical fauna,  and  the  Palaearctic  the  retreat  of  an  Ethiopian  type. 
During  the  Post-Pliocene  in  North  America,  Neotropical  genera 
were  to  Nearctic  as  12  to  29,  as  the  record  now  stands.  In  the 
Pliocene  beds  of  Pikermi  (Greece)  antelopes,  giraffes,  rhinoceros, 
hippopotamus,  huge  manis,*  monkeys,  monitors,  and  other  genera 
and  species  of  African  relationship  are  the  prevailing  forms. 

Still  earlier,  a  strong  mingling  of  Nearctic,  and  more  of  Neo- 
tropical types,  abounded  in  the  Palaearctic.  The  genera  Chelydra, 
Andrias,  Podocnemis,t  Platemys,  Caviiform,  Psammoryctid  and 
Hesperomys-like  Eodentia,  Opossums,  and  Raccoon-like  Carnivora. 

We  have,  then,  three  important  terms  from  which  to  derive  a 
theory  of  the  creation  :  1,  the  existing  six  faunae  bear  in  many  of 
their  parts  developmental  relations  to  one  another ;  2,  they  were 
preceded  immediately  by  faunae  similar  to  them  in  each  case,  but 
more  remotely  by  faunae  like  that  now  next  lower. 

On  the  whole,  there  can  be  no  doubt  of  the  truth  of  the  gen- 
eralization :  That  the  Southern  Hemisphere  is  a  geologic  stage 
hehind  the  Northern  Hemisphere  in  progress,  on  account  (1)  of 
its  perfection  in  types  extinct  in  the  Northern,  and  (2)  inferiority 
in  modern  types  prevalent  in  the  Northern. 

In  order,  however,  to  demonstrate  this  jDoint  more  fully,  let  us 

*  Ancylotherium,  Macrotherium. 

f  P.  howcrbanJcii  {Platemys^  Owen).     P.  Icevis  {JEinys,  Owen). 


ON  THE   ORIGIN   OF  GENERA.  ;121 

examine  to  what  extent  the  higher  types  exist  in  the  Southern 
and  lower  or  ancient  in  the  Northern. 

The  Percoid  fishes  and  their  allies  have  Australian  and  South 
American  representatives  in  their  fresh  waters,  but  they  are  as 
mere  outliers  of  the  great  mass  in  the  Northern  Hemisphere.  The 
higher  type  of  venomous  serpents  (Solenoglypha)  occur  in  both 
the  Ethiopian  and  Neotropical  regions,  but  they  j^reponderate  in 
the  Northern  Hemisphere.  The  higher  group  of  the  Saurians 
(the  Acrodonta)  abounds  in  the  Ethiopian  and  Australian  regions  ; 
they  are  as  abundant  in  the  Indian  and  Palaearctic  regions  of  the 
Northern  Hemisphere.  In  the  Southern,  also,  by  Uromastix  and 
the  Rynchocephalia,  they  approach  nearest  the  ancient  types  of  the 
Dicynodontia  and  the  Crocodilia.  Lacertidae,  and  not  Teidse, 
occur  in  the  Ethiopian  ;  but  they  are  but  a  proportion  of  the 
whole,  which  chiefly  exists  in  the  Nearctic. 

Eaniform,  and  not  Arciferous  Anura,  populate  South  Africa  ; 
they,  however,  form  but  a  small  proportion  compared  with  the 
great  series  of  the  Nearctic,  Palaearctic,  and  Palseotropical  regions. 
It  is,  however,  superior  in  Anura  to  the  Nearctic,  taken  by  itself. 

Rasorial  birds,  and  not  Pallastrae,  are  the  food  species  of  South 
Africa  ;  but  they  do  not  compare  in  abundance  or  size  with  those 
of  the  three  regions  just  mentioned. 

Moreover,  but  few  Clamatores  exist  in  either  Australia  or 
Ethiopia.  The  Oscine  types  are  abundant ;  nevertheless,  they  can 
not  be  compared  in  relative  abundance  with  those  of  the  northern 
regions.  It  must  also  be  remembered  that  the  migratory  capa- 
bilities of  birds  render  them  less  expressive  of  the  true  nature  of 
any  fauna. 

The  higher  family  of  the  Quadrumana,  the  Simiidae,  replaces 
in  Africa  the  Cebidae  of  the  Neotropical ;  they  are,  however,  most 
abundant  in  the  Palaeotropical  region,  in  the  other  hemisphere. 

There  are  two  ancient  or  inferior  types  of  the  Northern  Hemi- 
sphere :  First,  its  fishes,  the  Sturgeons  of  the  Nearctic  and  Palse- 
arctic,  and  the  Gars  of  the  Nearctic*  The  latter  only  have  rep- 
resentatives in  the  Southern  Hemisphere,  Polypterus  and  Cala- 
moichthys  in  Africa,  and  so  may  be  said  to  be  equally  distributed  ; 
but  the  former  are  confined  to  the  north.  We  do  not  know,  how- 
ever, whether  they  are  of  a  modern  or  an  ancient  type,  nor  do  we 


*  Subsequent  investigations  have  proved  that  Polypterus  and  Calamoichthys  are 
of  much  more  ancient  type  than  gars  and  sturgeons.     (Ed.  1886.) 


122  GENERAL  EVOLUTION. 

know  of  extinct  sturgeons  in  the  Southern  Hemisphere.  Indeed, 
the  Ganoid  series  is  not  well  defined  or  known  as  yet.  If,  as 
Agassiz  states,  the  Siluroids  pertain  to  it,  it  is  cosmopolitan, 
though  least  represented  in  the  Palasarctic. 

Second,  the  Tailed  or  Urodele  Batrachia.  This  order,  entirely 
characteristic  of  the  Northern  Hemisphere,  is  a  group  which  com- 
bines characters  of  Anura  with  those  of  the  ancient  forms,  and 
possesses  in  its  Nearctic  types  many  of  low  development.  The 
Gymnophidia  of  the  Southern  HemisjDhere  can  not  be  considered 
inferior  to  them.  In  the  possession  of  this  group  the  Northern 
Hemisphere  presents  its  first  element  of  inferiority. 

The  preceding  comparisons  indicate  also  the  relations  of  the 
regions  proper  to  each  other.  It  is  obvious  enough  that  the  Ethi- 
opian is  much  superior  to  the  two  others  of  the  Southern  Hemi- 
sphere. As  to  the  Australian  and  Neotropical,  the  former  must 
still  be  regarded  as  probably  the  most  ancient,  though  possessing 
at  the  same  time  a  much  stronger  admixture  of  northern  forms. 
I  liave  already  presented  the  relations,  with  the  inferior  forms  of 
each,  thus  :  * 

R.  Australis. — Inferior  in  possessing  Monotrematous  and  Marsu- 
pial Mammalia,  Pullastriform  and  Struthious  Birds,  Serpent- 
iform  Pleurodont  Lacertilia,  Arciferous  Batrachia,  Pleuro- 
dire  Tortoises,  its  Elapid  venomous  snakes,  and  the  whole 
Flora,  according  to  linger. 

B,  Neotropica. — Marsupial  and  Edentate  Mammalia,  Inferior 
Rodentia  and  Quadrumana,  Pleurodire  Tortoises,  Pleurodont 
Lacertilia,  Arciferous  Batrachia,  Clamatorial  and  Pullas- 
triform Birds,  Characin  and  Erythrinid  Malacopterigii. 

Conclusions, 

The  following  may  be  looked  upon  as  conclusions  which  have 
been  indicated  in  the  preceding  pages  : 

I.  Species  have  developed  from  pre-existent  species  by  an  in- 
herent tendency  to  variation,  and  have  been  preserved  in  given 
directions  and  repressed  in  others  by  the  operation  of  the  law  of 
natural  selection  (Darwin). 

II.  Genera  have  been  produced  by  a  system  of  retardation  or 
acceleration  in  the  development  of  individuals  ;  the  former  on 
pre-established,  the  latter  on  preconceived  lines  of  direction.     Or, 


«■ " 


Jour.  Acad.  Nat.  Sci.,"  Philada.,  1866,  p.  109. 


ON  THE   ORIGIN  OF   GENERA.  123 

in  other  words,  that  while  nature's  series  have  been  projected  in 
accordance  with  the  hiw  of  acceleration  and  retardation,  they  have 
been  limited,  modified,  and  terminated  by  the  law  of  natural  se- 
lection, which  may  itself  have  operated  in  part  by  the  same  law. 

III.  The  processes  of  development  of  specific  and  generic,  char- 
acters have  not  proceeded  pari  passu,  transitions  of  the  one  kind 
not  being  synchronous  with  transitions  of  the  other  ;  and  that, 
therefore,  species  may  be  transferred  from  one  genus  to  another 
without  losing  their  specific  characters,  and  genera  from  order  to 
order  without  losing  their  generic  characters. 

IV.  And  as  the  heterologous  terms  of  the  peculiar  homologous 
groups  present  an  ^^ inexact  parallelism"  with  each  other;  and 
as  types  related  by  inexact  parallelism  are  each  among  themselves 
exact  parallels  in  separate  series,  whose  earliest  members  present 
*^  exact  parallelisms  "  with  each  other,  it  follows — 

Y.  That  the  heterologous  terms  or  genera  in  the  later  series 
are  modified  descendants  of  those  of  the  earlier  series  ;  in  other 
words,  that  certain  groups  higher  than  genera  are  produced  from 
others  of  similar  high  value  by  "descent  with  modification." 

YI.  That  the  result  of  such  successional  metamorphoses  will 
be  expressed  in  geologic  history  by  more  or  less  abrupt  transitions 
or  expression-points,  rather  than  by  uniformly  gradual  succes- 
sions. 

Of  course,  under  the  conclusion  stated  in  Proposition  II,  the 
genus  Homo  has  been  developed  by  the  modification  of  some  pre- 
existent  genus.  All  his  traits  which  are  merely  functional  have, 
as  a  consequence,  been  produced  during  the  process.  Those  traits 
which  are  not  functional,  but  spiritual,  are  of  course  amenable  to 
a  different  class  of  laws,  which  belong  to  the  province  of  religion. 


III. 

ON  THE  THEOEY  OF  EVOLUTION". 

At  a  meeting  of  the  Philadelphia  Academy  of  Natural  Sci- 
ences, held  February  22,  1876,  Prof.  Cope  gave  a  history  of  the 
progress  of  the  doctrine  of  evolution  of  animal  and  vegetable 
types.  While  Darwin  has  been  its  prominent  advocate  within 
the  last  few  years,  it  was  first  presented  to  the  scientific  world,  in 
a  rational  form,  by  Lamarck,  of  Paris,  at  the  commencement  of 
the  present  century.  Owing  to  the  adverse  influence  of  Cuvier, 
the  doctrine  remained  dormant  for  half  a  century,  and  Darwin 
resuscitated  it,  making  important  additions  at  the  same  time. 
Thus  Lamarck  found  the  variations  of  species  to  be  the  primary 
evidence  of  evolution  by  descent.  Darwin  enunciated  the  law  of 
*^ natural  selection"  as  a  result  of  the  struggle  for  existence,  in 
■accordance  with  which  "the  fittest"  only  survive.  This  law, 
now  generally  accepted,  is  Darwin's  principal  contribution  to  the 
doctrine.  It,  however,  has  a  secondary  position  in  relation  to 
the  origin  of  variation,  which  Lamarck  saw,  but  did  not  account 
for,  and  which  Darwin  has  to  assume  in  order  to  have  materials 
from  which  a  "  natural  selection  "  can  be  made. 

The  relations  exhibited  by  fully  grown  animals  and  plants 
with  transitional  or  embryonic  stages  of  other  animals  and  plants, 
had  attracted  the  attention  of  anatomists  at  the  time  of  Lamarck. 
Some  naturalists  deduced  from  this  now  universally  observed 
phenomenon  that  the  lower  types  of  animals  were  merely  re- 
pressed conditions  of  the  higher,  or,  in  other  words,  were  embry- 
onic stages  become  permanent.  But  the  resemblances  do  not 
usually  extend  to  the  entire  organism,  and-  the  parallels  are  so 
incomplete  that  this  view  of  the  matter  was  clearly  defective, 
and  did  not  constitute  an  explanation.  Some  embryologists,  as 
Lereboullet  and  Agassiz,  asserted  that  no  argument  for  a  doctrine 
of  descent  could  be  drawn  from  such  facts. 

The  speaker,  not  adopting  either  view,  made  a  full  investiga- 


ON  THE  THEORY   OF  EVOLUTION.  125 

tion  into  the  later  embryonic  stages,  chiefly  of  the  skeleton  of  the 
Batrachia,  in  1865,  and  Prof.  Hyatt,  of  Salem,  Mass.,  at  the 
same  time  made  similar  studies  in  the  development  of  the  Ammo- 
nites and  Nautili.  The  results  as  bearing  on  the  doctrine  of  evo- 
lution were  published  in  1869  (in  ^^The  Origin  of  Genera").  It 
was  there  pointed  out  that  the  most  nearly  related  forms  of  ani- 
mals do  present  a  relation  of  repression  and  advance,  or  of  perma- 
nent embryonic  and  adult  type,  leaving  no  doubt  that  the  one  is 
descended  from  the  other.  This  relation  was  termed  exact  paral- 
lelism. It  was  also  shown  that,  if  the  embryonic  form  were  the 
parent,  the  advanced  descendant  was  produced  by  an  increased 
rate  of  growth,  which  phenomenon  was  called  acceleration ;  but 
that  if  the  embryonic  type  were  the  offspring,  then  its  failure  to 
attain  to  the  condition  of  the  parent  is  due  to  the  supervention  of 
a  slower  rate  of  growth  ;  to  this  phenomenon  the  term  retarda- 
tion was  applied.  It  was  then  shown  that  the  inexact  parallelism 
was  the  result  of  U7iequal  acceleration  or  retardation  ;  that  is,  ac- 
celeration affecting  one  organ  or  part  more  than  another,  thus 
disturbing  the  combination  of  characters  which  is  necessary  for 
the  state  of  exact  parallelism  between  the  perfect  stage  of  one 
animal  and  the  transitional  state  of  another.  Moreover,  accelera- 
tion implies  constant  addition  to  the  parts  of  an  animal,  while  re- 
tardation implies  continual  subtraction  from  its  characters,  or 
atrophy.  He  had  also  shown  (''Method  of  Creation,"  1871)  that 
the  additions  either  appeared  as  exact  repetitions  of  pre-existent 
parts,  or  as  modified  repetitions,  the  former  resulting  in  simple, 
the  latter  in  more  complex  organisms. 

Prof.  Haeckel,  of  Jena,  has  added  the  keystone  to  the  doc- 
trine of  evolution  in  his  gastrsea  theory.  Prior  to  this  generaliza- 
tion it  had  been  impossible  to  determine  the  true  relation  existing 
between  the  four  types  of  embryonic  growth,  or,  to  speak  other- 
wise, than  that  they  are  inherently  distinct  from  each  other. 
But  Haeckel  has  happily  determined  the  existence  of  identical 
stages  of  growth  in  all  of  the  types  of  eggs,  the  last  of  which  is 
the  gastrula ;  and  beyond  which  the  identity  ceases.  Not  that 
the  four  types  of  gastrula  are  without  difference,  but  this  differ- 
ence maybe  accounted  for,  on  plain  principles.  In  1874,  Haeckel, 
in  his  "Anthropogenic,"  recognizes  the  importance  of  the  irregu- 
larity of  time  of  appearance  of  the  different  characters  of  animals, 
during  the  period  of  growth,  as  affecting  their  permanent  struct- 
ure.    While  maintaining  the  view  that  the  low  forms  represent 


126  GENERAL  EVOLUTION. 

the  transitionaL  stages  of  the  higher,  he  proceeds  to  account  for 
the  want  of  exact  correspondence  exhibited  by  them  at  the  present 
time,  by  reference  to  this  principle.  He  believes  that  the  rela- 
tion of  parent  and  descendant  has  been  concealed  and  changed 
by  subsequent  modifications  of  the  order  of  appearance  of  charac- 
ters in  growth.  To  the  original,  simple  descent  he  applies  the 
term  palingenesis  ;  to  the  modified  and  later  growth,  coenogenesis. 
The  causes  of  the  change  from  palingenesis  to  coenogenesis  he  re- 
gards as  three,  viz.,  acceleration,  retardation,  and  heterotopy. 

It  is  clear  that  the  two  types  of  growth  distinguished  by  Prof. 
Haeckel  are  those  which  had  been  pointed  out  by  Prof.  Cope  in 
"The  Origin  of  Genera,"  as  producing  the  relations  of  "exact" 
and  "inexact  parallelism";  and  that  his  explanation  of  the 
origin  of  the  latter  relation  by  acceleration  or  retardation  is  the 
same  as  that  of  the  latter  essay.  The  importance  which  he  at- 
taches to  the  subject  was  a  source  of  gratification  to  the  speaker, 
as  it  was  a  similar  impression  that  led  to  the  publication  of  "  The 
Origin  of  Genera  "  in  1869. 

It  remains  to  observe  that  the  phenomena  of  exact  parallelism 
or  palingenesis  are  quite  as  necessarily  accounted  for  on  the  prin- 
ciple of  acceleration  or  retardation  as  are  those  of  inexact  paral- 
lelism or  coenogenesis.  Were  all  parts  of  the  organism  acceler- 
ated or  retarded  at  a  like  rate,  the  relation  of  exact  parallelism 
would  never  be  disturbed  ;  while  the  inexactitude  of  the  parallel- 
ism will  depend  on  the  number  of  variations  in  the  rate  of  growth 
of  different  organs  of  the  individual,  with  additions  introduced 
from  time  to  time.  Hence  it  may  be  laid  down  that  synchronous 
acceleration  or  retardation  produces  exact  parallelism,  and  lietero- 
chronous  acceleration  or  retardation  produces  inexact  parallel- 
ism. 

In  conclusion,  it  may  be  added  that  acceleration  of  the  seg- 
mentation of  the  protoplasma  or  animal  portion  of  the  primordial 
Qgg,  or  retardation  of  segmentation  of  the  deutoplasma  or  vegeta- 
tive half  of  the  Qgg,  or  both,  or  the  same  relation  between  the 
growth  of  the  circumference  and  center  of  the  egg,  has  given  rise 
to  the  four  types  which  the  segmentation  now  presents. 

An  analysis  of  the  laws  of  evolution  may  be  tabulated  as  fol- 
lows : 


ON  THE  THEORY  OF  EVOLUTION. 


127 


-I:? 


1      ^.  (  Exact  repetition .^ 

acceUrahon,  \  Modified  repetition I 

which  proceeds  by  ]  g^^^^^^^pyj - 

retardation^  j  Exact  atrophy ^ 

Avhich  proceeds  by  (  Inexact  atrophy  (or  senility  r-' ^j. 


as 

o  Si: 


P 


t< 


O    Co 

s  2. 

Co      i_l 


* 
* 


a,  a 
O   £1 

t-b  05 


*  So  called  by  Prof.  Hyatt. 


IV. 
ON   THE   HYPOTHESIS   OF  EVOLUTION: 

PHYSICAL  AND   METAPHYSICAL. 

"  Man  shall  not  live  by  bread  alone,  but  by  every  word  that  proceedeth  out  of  the 

mouth  of  God  shall  man  live." 

There  is  apparently  considerable  repugnance  in  the  minds  of 
many  excellent  people  to  the  acceptance,  or  eyen  consideration,  of 
the  hypothesis  of  development,  or  that  of  the  gradual  creation  by 
descent,  with  modifications  from  the  simplest  beginnings,  of  the 
different  forms  of  the  organic  world.  This  objection  probably 
results  from  two  considerations  :  first,  that  the  human  sj^ecies  is 
certainly  involved,  and  man's  descent  from  an  ape  asserted ;  and, 
secondly,  that  the  scheme  in  general  seems  to  conflict  with  that 
presented  by  the  Mosaic  account  of  the  Creation,  which  is  regarded 
as  communicated  to  its  author  by  an  infallible  inspiration. 

As  the  truth  of  the  hypothesis  is  held  to  be  infinitely  probable 
by  a  majority  of  the  exponents  of  the  natural  sciences  at  the  pres- 
ent day,  and  is  held  as  absolutely  demonstrated  by  another  por- 
tion, it  behooves  those  interested  to  restrain  their  condemnation, 
and  on  the  other  hand  to  examine  its  evidences,  and  look  any  con- 
sequent necessary  modification  of  our  metaphysical  or  theological 
views  squarely  in  the  face. 

The  following  pages  state  a  few  of  the  former  ;  if  they  suggest 
some  of  the  latter,  it  is  hoped  that  they  may  be  such  as  any  logical 
mind  would  deduce  from  the  premises.  That  they  will  coincide 
with  the  spirit  of  the  most  advanced  Christianity,  I  have  no 
doubt ;  and  that  they  will  add  an  appeal  through  the  reason  to 
that  direct  influence  of  the  Divine  Spirit  which  should  control  the 
motives  of  human  action,  seems  an  unavoidable  conclusion. 

I.    PHYSICAL   EVOLUTIOK. 

It  is  well  known  that  a  species  is  usually  represented  by  a  great 
number  of  individuals,  distinguished  from  all  other  similar  associ- 


ON  THE  HYPOTHESIS   OF  EVOLUTION.  129 

ations  by  more  or  less  numerous  points  of  structure,  color,  size, 
etc.,  and  by  habits  and  instincts  also,  to  a  certain  extent;  that 
the  individuals  of  such  associations  reproduce  their  like,  and  can 
not  be  produced  by  individuals  of  associations  or  species  v^^hich 
present  differences  of  structure,  color,  etc.,  as  defined  by  natural- 
ists ;  that  the  individuals  of  any  such  series  or  species  are  incapa- 
ble of  reproducing  with  those  of  any  other  species,  with  some 
exceptions  ;  and  that  in  the  latter  cases  the  offspring  are  usually 
entirely  infertile. 

The  hypothesis  of  Cuvier  assumes  that  each  species  was  created 
by  divine  power  as  we  now  find  it  at  some  definite  point  of  geo- 
logic time.  The  paleontologist  holding  this  view  sees,  in  accord- 
ance therewith,  a  succession  of  creations  and  destructions  marking 
the  history  of  life  on  our  planet  from  its  commencement. 

The  development  hypothesis  states  that  all  existing  species 
have  been  derived  from  species  of  pre-existent  geological  periods, 
as  offspring  or  by  direct  descent ;  that  there  have  been  no  total 
destructions  of  life  in  past  time,  but  only  a  transfer  of  it  from 
place  to  place,  owing  to  changes  of  circumstance  ;  that  the  types 
of  structure  become  simpler  and  more  similar  to  each  other  as  we 
trace  them  from  later  to  earlier  periods  ;  and  that  finally  we  reach 
the  simplest  forms  consistent  with  one  or  several  original  parent 
types  of  the  great  divisions  into  which  living  beings  naturally  fall. 

It  is  evident,  therefore,  that  the  hypothesis  does  not  include 
change  of  species  by  hybridization,  nor  allow  the  descent  of  living 
species  from  any  other  living  species  :  both  these  propositions  are 
errors  of  misapprehension  or  misrepresentation. 

In  order  to  understand  the  history  of  creation  of  a  complex 
being,  it  is  necessary  to  analyze  it  and  ascertain  of  what  it  con- 
sists. In  analyzing  the  construction  of  an  animal  or  plant  we 
readily  arrange  its  characters  into  those  which  it  possesses  in  com- 
mon with  other  animals  or  plants,  and  tliose  in  which  it  resem- 
bles none  other  :  the  latter  are  its  i7icUvidual  characters,  consti- 
tuting its  individuality.  Next,  we  find  a  large  body  of  characters, 
generally  of  a  very  obvious  kind,  which  it  possesses  in  common 
with  a  generally  large  number  of  individuals,  which,  taken  col- 
lectively, all  men  are  accustomed  to  call  a  species  ;  these  charac- 
ters we  consequently  name  specific.  Thirdly,  we  find  characters, 
generally  in  parts  of  the  body  which  are  of  importance  in  the  ac- 
tivities of  the  animal,  or  which  lie  in  near  relation  to  its  mechan- 
ical construction  in  details,  which  are  shared  by  a  still  larger 

9 


130  GENERAL  EVOLUTION. 

number  of  individuals  than  those  which  were  similar  in  specific 
characters.  In  other  words,  it  is  common  to  a  large  number  of 
species.  This  kind  of  character  we  call  generic^  and  the  grouping 
it  indicates  is  a  genus. 

Farther  analysis  brings  to  light  characters  of  organism  which 
are  common  to  a  still  greater  number  of  individuals  ;  this  we  call 
Si  family  character.  Those  which  are  common  to  still  more  nu- 
merous individuals  are  the  ordinal:  they  are  usually  found  in 
parts  of  the  structure  which  have  the  closest  connection  with  the 
whole  life-history  of  the  being.  Finally,  the  individuals  compos- 
ing many  orders  will  be  found  identical  in  some  important  char- 
acter of  the  systems  by  which  ordinary  life  ic  maintained,  as  in 
the  nervous  and  circulatory  :  the  divisions  thus  outlined  are  called 
classes. 

By  this  process  of  analysis  we  reach  in  our  animal  or  j^lant 
those  peculiarities  which  are  common  to  the  whole  animal  or  vege- 
table kingdom,  and  then  we  have  exhausted  the  structure  so  com- 
pletely that  we  have  nothing  remaining  to  take  into  account  beyond 
the  cell-structure  or  homogeneous  protoplasm  by  which  we  know 
that  it  is  organic,  and  not  a  mineral. 

The  history  of  the  origin  of  a  type,  as  species,  genus,  order, 
etc.,  is  simply  the  history  of  the  origin  of  the  structure  or  struct- 
ures which  define  those  groups  respectively.  It  is  nothing  more 
nor  less  than  this,  whether  a  man  or  an  insect  be  the  object  of 
investigation. 

EVIDENCES   OF   DEEIVATION. 

a.   Of  Specific  Characters. 

The  evidences  of  derivation  of  species  from  species,  within  the 
limits  of  the  genus,  are  abundant  and  conclusive.  In  the  first 
place,  the  rule  which  naturalists  observe  in  defining  species  is  a 
clear  consequence  of  such  a  state  of  things.  It  is  not  amount  and 
degree  of  difference  that  determine  the  definition  of  species  from 
species,  but  it  is  the  permanency  of  the  characters  in  all  cases  and 
under  all  circumstances.  Many  species  of  the  systems  include  va- 
rieties and  extremes  of  form,  etc.,  which,  were  they  at  all  times 
distinct,  and  not  connected  by  intermediate  forms,  would  be  esti- 
mated as  species  by  the  same  and  other  writers,  as  can  be  easily 
seen  by  reference  to  their  works. 

Thus,  species  are  either  "restricted  "  or  '^protean,"  the  latter 


ON  THE   HYPOTHESIS  OF  EVOLUTION.  131 

embracing  many,  the  former  few  variations  ;  and  the  varieties  in- 
cluded by  the  protean  species  are  often  as  different  from  each  other 
in  their  typical  forms  as  are  the  ** restricted"  species.  As  an  ex- 
ample, the  species  Homo  sapiens  (man)  will  suffice.  His  primary 
varieties  are  as  distinct  as  the  species  of  many  well-known  genera, 
but  can  not  be  defined,  owing  to  the  existence  of  innumerable  in- 
termediate forms  between  them. 

As  to  the  common  origin  of  such  '^varieties"  of  the  protean 
species,  naturalists  never  had  any  doubt ;  yet  when  it  comes  to  the 
restricted  ^'^  species,"  the  anti-developmentalist  denies  it  in  toto. 
Thus  the  varieties  of  most  of  the  domesticated  animals  are  some 
of  them  known — others  held  with  great  probability  to  have  had  a 
common  origin.  Varieties  of  plumage  in  fowls  and  canaries  are 
of  every-day  occurrence,  and  are  produced  under  our  eyes.  The 
cart-horse  and  racer,  the  Shetland  pony  and  the  Norman,  are 
without  doubt  derived  from  the  same  parentage.  The  varieties  of 
pigeons  and  ducks  are  of  the  same  kind,  but  not  every  one  is 
aware  of  the  extent  and  amount  of  such  variations.  The  varieties 
in  many  characters  seen  in  hogs  and  cattle,  especially  when  exam- 
ples from  distant  countries  are  compared,  are  very  striking,  and 
are  confessedly  equal  in  degree  to  those  found  to  define  species  in 
a  state  of  nature  :  here,  however,  they  are  not  definitive. 

It  is  easy  to  see  that  all  that  is  necessary  to  produce  in  the 
mind  of  the  anti-developmentalist  the  illusion  of  distinct  origin 
by  creation  of  many  of  these  forms  would  be  to  destroy  a  number 
of  the  intermediate  conditions  of  specific  form  and  structure,  and 
thus  to  leave  remaining  definable  groups  of  individuals,  and  there- 
fore "species." 

That  such  destructions  and  extinctions  have  been  going  no 
ever  since  the  existence  of  life  on  the  globe  is  well  known.  That 
it  should  affect  intermediate  forms,  such  as  bind  together  the 
types  of  a  protean  species  as  well  as  restricted  species,  is  equally 
certain.  That  its  result  has  been  to  produce  definaUe  species  can 
not  be  denied,  especially  in  consideration  of  the  following  facts  : 
Protean  species  nearly  always  have  a  wide  geographical  distribu- 
tion. Thev  exist  under  more  varied  circumstances  than  do  indi- 
viduals  of  a  more  restricted  species.  The  subordinate  variations 
of  the  protean  species  are  generally,  like  the  restricted  species, 
confined  to  distinct  subdivisions  of  the  geographical  area  which 
the  whole  occupies.  As  in  geological  time  changes  of  level  have 
separated  areas  once  continuous  by  bodies  of  water  or  high  mount- 


132  GENERAL  EVOLUTION. 

ain-ranges,  so  have  vast  numbers  of  individuals  occupying  sucli 
areas  been  destroyed.  Important  alterations  of  temperature,  or 
great  changes  in  abundance  or  character  of  vegetable  life  over 
given  areas,  would  produce  the  same  result. 

This  part  of  the  subject  might  be  prolonged,  were  it  necessary, 
but  it  has  been  ably  discussed  by  Darwin.  The  rationale  of  the 
^^  origin  of  species,"  as  stated  by  him,  may  be  examined  a  few 
pages  farther  on. 

p.  Of  the  Characters  of  Higher  Groups. 

a.  Relations  of  Structures. — The  evidences  of  derivative  origin 
of  the  structures  defining  the  groups  called  genera,  and  all  those 
of  higher  grade,  are  of  a  very  different  character  from  those  dis- 
cussed in  relation  to  specific  characters  ;  they  are  more  diflScult  of 
observation  and  explanation. 

First  :  It  would  appear  to  be  supposed  by  many  that  the  crea- 
tion of  organic  types  was  an  irregular  and  capricious  process, 
variously  pursued  by  its  Author  as  regards  time  and  place,  and 
without  definite  final  aim  ;  and  this  notwithstanding  the  wonder- 
ful evidences  we  possess,  in  the  facts  of  astronomy,  chemistry, 
sound,  etc.,  of  his  adhesion  to  harmonious  and  symmetrical 
sequences  in  his  modes  and  plans. 

Such  regularity  of  plan  is  found  to  exist  in  the  relations  of  the 
great  divisions  of  the  animal  and  vegetable  kingdoms  as  at  present 
existing  on  the  earth.  Thus,  with  animals  we  have  a  great  class 
of  species  which  consists  of  nothing  more  than  masses  or  cells  of 
protoplasmic  matter,  without  distinct  organs ;  or  the  Protozoa. 
We  have  then  the  Coelenterata  (example,  corals),  where  the  organ- " 
ism  is  composed  of  many  cells  arranged  in  distinct  parts,  but 
where  a  single  very  simple  system  of  organs,  forming  the  only  in- 
ternal cavity  of  the  body,  does  the  work  of  the  many  systems  of 
the  more  complex  animals.  Next,  the  Echinodermata  (such  as 
star-fish)  present  us  with  a  body  containing  distinct  systems  of 
organs  inclosed  in  a  visceral  cavity,  including  a  rudimental  nerv- 
ous system  in  the  form  of  a  ring.  In  the  Molluscs  to  this  con- 
dition is  added  further  complication,  including  extensions  of 
the  nervous  system  from  the  ring  as  a  starting-point,  and  a 
special  organ  for  a  heart.  In  the  Articulates  (crabs,  insects)  we 
have  like  complications,  and  a  long  distinct  nervous  axis  on  the 
lower  surface  of  the  body.  The  last  branch  or  division  of  ani- 
mals is  considered  to  be  higher,  because  all  the  systems  of  life 


ON"   THE   HYPOTHESIS  OF  EYOLUTIOX.  133 

organs  are  most  complex  or  specialized.  The  neryous  rino-  ig 
almost  obliterated  by  a  great  enlargement  of  its  nsual  gano-lja, 
thus  become  a  brain,  which  is  succeeded  by  a  long  axis  on  the 
upper  side  of  the  body.  This  and  other  points  define  the  Ver- 
tebrata. 

Plans  of  structure,  independent  of  the  simplicity  or  perfection 
of  the  special  arrangement  or  structure  of  organs,  also  define 
these  great  groups.  Thus  the  Protozoa  present  a  spiral,  the 
Coelenterata  a  radiate,  the  Echinodermata  a  bilateral  radiate  plan. 
The  Articulates  are  a  series  of  external  rings,  each  in  one  or  more 
respects  repeating  the  others.  The  Molluscs  are  a  sac,  while  a 
ring  above  a  ring,  joined  together  by  a  solid  center-piece,  repre- 
sents the  plan  of  each  of  the  many  segments  of  the  Vertebrates 
which  give  the  members  of  that  branch  their  form. 

These  bulwarks  of  distinction  of  animal  types  are  entered  into 
here  simply  because  they  are  the  most  inviolable  and  radical  of 
those  with  which  we  have  to  deal,  and  to  give  the  anti-develop- 
mentalist  the  best  foothold  for  his  position.  I  will  only  allude  to 
the  relations  of  their  points  of  approach  as  these  are  affected  by 
considerations  afterward  introduced. 

The  Vertebrates  approach  the  Molluscs  closely  at  the  lowest 
extreme  of  the  former  and  higher  of  the  latter.  The  lamprey 
eels  of  the  one  joossess  several  characters  in  common  with  the 
cuttle-fish  or  squids  of  the  latter.  The  amj)hioxus  is  called  the 
lowest  Vertebrate,  and,  though  it  is  nothing  else,  the  definition  of 
the  division  must  be  altered  to  receive  it ;  it  has  no  brain  ! 

The  lowest  forms  of  the  Molluscs  and  Articulates  are  scarcely 
distinguishable  from  each  other,  so  far  as  adhesion  to  the  "plan  " 
is  concerned,  and  some  of  the  latter  division  are  very  near  certain 
Echinodermata.  As  we  approach  the  boundary-lines  of  the  two 
lowest  divisions,  the  approaches  become  equally  close. 

More  instructive  is  the  evidence  of  the  relation  of  the  subordi- 
nate classes  of  any  one  of  these  divisions.  The  conditions  of 
those  organs  or  parts  which  define  classes  exhibit  a  regular  rela- 
tion, commencing  with  simplicity  and  ending  with  complication  ; 
first  associated  with  weak  exhibitions  of  the  highest  functions  of 
the  nervous  system — at  the  last  displaying  the  most  exalted  traits 
found  in  the  series. 

For  example  :  In  the  classes  of  Vertebrates  we  find  the  lowest 
neryous  system  presents  great  simplicity — the  brain  can  not  be 
recognized  ;  next  (in  lampreys),  the  end  of  the  nervous  axis  is 


134  GENERAL   EVOLUTION. 

subdivided,  but  scarcely  according  to  the  complex  type  that  fol- 
lows. In  fishes  the  cerebellum  and  cerebral  hemispheres  are 
minute,  and  the  intermediate  or  optic  lobes  very  large  :  in  the 
reptiles  the  cerebral  hemispheres  exceed  the  optic  lobes,  while  the 
cerebellum  is  smaller.  In  birds  the  cerebellum  becomes  complex 
and  the  cerebrum  greatly  increases.  In  mammals  the  cerebellum 
increases  in  complexity  or  number  of  parts,  the  o^^tic  lobes 
diminish,  while  the  cerebral  hemispheres  become  wonderfully 
complex  and  enlarged,  bringing  us  to  the  highest  development, 
in  man. 

The  history  of  the  circulatory  system  in  the  Vertebrates  is  the 
same.  First,  a  heart  with  one  chamber,  then  one  with  two  divis- 
ions :  three  divisions  belong  to  a  large  series,  and  the  highest 
possess  four.  The  origins  of  the  great  artery  of  the  body,  the 
aorta,  are  first  five  on  each  side  :  they  lose  one  in  the  succeeding 
class  in  the  ascending  scale,  and  one  in  each  succeeding  class  or 
order,  till  the  Mammalia,  including  man,  present  us  with  but  one 
on  one  side. 

From  an  infinitude  of  such  considerations  as  the  above,  we 
derive  the  certainty  that  the  general  arrangement  of  the  various 
grouj^s  of  the  organic  world  is  in  scales,  the  subordinate  within 
the  more  comprehensive  divisions.  The  identification  of  all  the 
23arts  in  such  a  complexity  of  organism  as  the  highest  animals 
present  is  a  matter  requiring  much  care  and  attention,  and  con- 
stitutes the  study  of  homologies.  Its  pursuit  has  resulted  in  the 
demonstration  that  every  individual  of  every  species  of  a  given 
branch  of  the  animal  kingdom  is  composed  of  elements  common 
to  all,  and  that  the  differences  which  are  so  radical  in  the  higher 
groups  are  but  the  modifications  of  the  same  elemental  parts, 
representing  completeness  or  incom^Dleteness,  obliteration  or  sub- 
division. Of  the  former  character  are  rudimental  organs,  of 
which  almost  every  species  possesses  an  example  in  some  part  of 
its  structure. 

But  we  have  other  and  still  more  satisfactory  evidence  of  the 
meaning  of  these  relations.  By  the  study  of  embryology  we  can 
prove  most  indubitably  that  the  simple  and  less  complex  are  in- 
ferior to  the  more  complex.  Selecting  the  Vertebrates  again  as 
an  example,  the  highest  form  of  mammal — e.  g.,  man — presents 
in  his  earliest  stages  of  embryonic  growth  a  skeleton  of  cartilage, 
like  that  of  the  lamprey ;  he  also  possesses  five  origins  of  the 
aorta  and  five  slits  on  the  neck  :  both  which  characters  belong  to 


ox  THE  HYPOTHESIS   OF  EVOLUTION.  135 

the  lamprey  and  the  shark.  If  the  whole  number  of  these  parts 
does  not  co-exist  in  the  embryonic  man,  we  find  in  embryos  of 
lower  forms,  more  nearly  related  to  the  lamprey,  that  they  do. 
Later  in  the  life  of  the  mammal  but  four  aortic  origins  are  found, 
which  arrangement,  with  the  heart  now  divided  into  two  cham- 
bers, from  a  beginning  as  a  simple  tube,  is  characteristic  of  the 
class  of  Vertebrates  next  in  order — the  bony  fishes.  The  optic 
lobes  of  the  human  brain  have  also  at  this  time  a  great  predomi- 
nance in  size — a  character  above  stated  to  be  that  of  the  same 
class.  With  advancing  development  the  infant  mammal  follows 
the  scale  already  pointed  out.  Three  chambers  of  the  heart  and 
three  aortic  origins  follow,  presenting  the  condition  permanent 
in  the  Batrachia ;  and  two  origins,  with  enlarged  cerebral  hemi- 
spheres of  the  brain,  resemble  the  reptilian  condition.  Four 
heart-chambers,  and  one  aortic-root  on  each  side,  with  slight 
development  of  the  cerebellum,  follow,  all  characters  defining  the 
crocodiles,  and  immediately  precede  the  special  conditions  defin- 
ing the  mammals.  These  are,  the  single  aorta-root  from  one 
side,  and  the  full  development  of  the  cerebellum  ;  later  comes 
that  of  the  cerebrum  also  in  its  higher  mammalian  and  human 
traits. 

Thus  we  see  the  order  already  pointed  out  to  be  true,  and  to 
be  an  ascending  one.  This  is  the  more  evident  as  each  type  or 
class  passes  through  the  conditions  of  those  below  it,  as  did  the 
mammal ;  each  scale  being  shorter  as  its  highest  terminus  is 
lower.  Thus  the  crocodile  passes  through  the  stage  of  the  lam- 
prey, the  fish,  the  batrachian,  and  the  reptile  proper. 

h.  In  Time, — We  have  thus  a  scale  of  relations  of  existing 
forms  of  animals  and  plants  of  a  remarkable  kind,  and  such  as 
to  stimulate  greatly  our  inquiries  as  to  its  significance.  When 
we  turn  to  the  remains  of  tlie  past  creation,  preserved  to  us  in 
the  deposits  continued  throughout  geologic  time,  we  are  not 
disappointed,  for  great  light  is  at  once  thrown  upon  the  sub- 
ject. 

We  find,  in  brief,  that  the  lowest  division  of  the  animal  king- 
dom appeared  first,  and  long  before  any  type  of  a  higher  charac- 
ter was  created.  The  Protozoon,  Eozoon,  is  the  earliest  of 
animals  in  geologic  time,  and  represents  the  lowest  type  of 
animal  life  now  existing.  We  learn  also  that  the  highest  branch 
appeared  last.  No  remains  of  Vertebrates  have  been  found  below 
the  lower  Devonion  period,  or  not  until  the  Echinoderms  and 


136  GENERAL  EVOLUTION. 

Molluscs  had  reached  a  great  pre-emmeuce.  It  is  difficult  to  be 
sure  whether  the  Protozoa  had  a  greater  numerical  extent  in  the 
earliest  periods  than  now,  but  there  can  be  no  doubt  that  the 
Coelenterata  (corals)  and  Echinoderms  (crinoids)  greatly  exceeded 
their  present  bounds  in  Paleozoic  time,  so  that  those  at  present 
existing  are  but  a  feeble  remnant.  If  we  examine  the  sub- 
divisions known  as  classes,  evidence  of  the  nature  of  the  succes- 
sion of  creation  is  still  more  conclusive.  The  most  poljp-like  of 
the  Molluscs  (Brachiopoda)  constituted  the  great  mass  of  its  repre- 
sentatives during  Paleozoic  time.  Among  Vertebrates  the  fishes 
appear  first,  and  had  their  greatest  development  in  size  and  num- 
bers during  the  earliest  periods  of  the  existence  of  the  division. 
Batrachia  were  much  the  largest  and  most  important  of  land  ani- 
mals during  the  Carboniferous  period,  while  the  higher  Verte- 
brates were  unknown.  The  later  Mesozoic  j^eriods  saw  the  reign 
of  reptiles,  whose  position  in  structural  develojoment  has  been 
already  stated.  Finally,  the  most  perfect,  the  mammal,  came 
upon  the  scene,  and  in  his  humblest  rej^resentatives.  In  Tertiary 
times  Mammalia  supplanted  the  reptiles  entirely. 

Thus  the  structural  relations,  the  embryonic  characters,  and 
the  successive  appearance  in  time  of  animals  coincide.  The  same 
is  very  probably  true  of  plants. 

That  the  existing  state  of  the  geological  record  of  organic 
types  should  be  regarded  as  anything  but  a  fragment  is,  from 
our  standpoint,  quite  preposterous.  And,  more,  it  may  be  as- 
sumed with  safety  that  when  completed  it  will  furnish  us  with 
a  series  of  regular  successions,  with  but  slight  and  regular  in- 
terruptions, if  any,  from  the  species  which  represented  the  sim- 
plest beginnings  of  life  at  the  dawn  of  creation,  to  those  which 
have  displayed  complication  and  power  in  later  or  in  the  present 
periods. 

For  the  labors  of  the  paleontologist  are  daily  bringing  to  light 
structures  intermediate  between  those  never  before  so  connected, 
and  thus  creating  lines  of  succession  where  before  were  only  in- 
terruptions. Many  such  instances  might  be  adduced  :  two  might 
be  selected  as  examiDles  from  American  paleontology  ;  *  i.  e. ,  the 

*  Prof.  Huxley,  in  the  last  anniversary  lecture  before  the  Geological  Society 
of  London,  recalls  his  opinion,  enunciated  in  1862,  that  "the  positively-ascertained 
truths  of  Paleontology  "  negative  "  the  doctrines  of  progressive  modification,  which 
suppose  that  modification  to  have  taken  place  by  a  necessary  progress  from  more  to 
less  embryonic  forms,  from  more  to  less  generalized  types,  within  the  limits  of  the 


ox  THE  HYPOTHESIS  OF  EVOLUTION.  137 

near  approach  to  birds  made  by  the  reptiles  Laelaps  and  Megadac- 
tylus,  and  the  combination  of  characters  of  the  old  genera  Ich- 
thyosaurus and  Plesiosaurus  in  the  Polycotylus  of  Kansas. 

We  had  no  more  reason  to  look  for  intermediate  or  connectino- 
forms  between  such  types  as  these  than  between  any  others  of 
similar  degree  of  remove  from  each  other  with  which  we  are  ac- 


period  represented  by  the  fossiliferous  rocks ;  that  it  shows  no  evidence  of  such 
modification ;  and,  as  to  the  nature  of  that  modification,  it  yields  no  evidence  what- 
soever  that  the  earlier  members  of  any  long-continued  group  were  more  generalized 
in  structure  than  the  later  ones." 

Respecting  this  position,  he  says  :  "  Thus  far  I  have  endeavored  to  expand  and 
enforce  by  fresh  arguments,  but  not  to  modify  in  any  important  respect,  the  ideas 
submitted  to  you  on  a  former  occasion.  But  when  I  come  to  the  propositions  re- 
specting progressive  modification,  it  appears  to  me,  with  the  help  of  the  new  light 
which  has  broken  from  various  quarters,  that  there  is  much  ground  for  softening 
the  somewhat  Brutus-like  severity  with  which  I  have  dealt  with  a  doctrine  for  the 
truth  of  which  I  should  have  been  glad  enough  to  be  able  to  find  a  good  foundation 
in  1862.  So  far  indeed  as  the  Invertebrata  and  the  lower  Vertebrata  are  concerned, 
the  facts  and  the  conclusions  which  are  to  be  drawn  from  them  appear  to  me  to  re- 
main what  they  were.  For  anything  that  as  yet  appears  to  the  contrary,  the  earliest 
known  Marsupials  may  have  been  as  highly  organized  as  their  living  congeners ;  the 
Permian  lizards  show  no  signs  of  inferiority  to  those  of  the  present  day ;  the  laby- 
rinthodonts  can  not  be  placed  below  the  living  salamander  and  triton ;  the  Devo- 
nian ganoids  are  closely  related  to  polypterus  and  lepidosiren." 

To  this  it  may  be  replied:  1.  The  scale  of  progression  of  the  Vertebrata  is 
measured  by  the  condition  of  the  circulatory  system,  and  in  some  measure  by  the 
nervous,  and  not  by  the  osseous :  tested  by  this  scale,  there  has  been  successional 
complication  of  structure  among  Vertebrata  in  time.  2.  The  .question  with  the 
evolutionist  is,  not  what  types  have  persisted  to  the  present  day,  but  the  order  in 
which  types  appeared  in  time.  3.  The  Marsupials,  Permian  saurians,  labyrintho- 
donts,  and  Devonian  ganoids  are  remarkably  generalized  groups,  and  predecessors  of 
types  widely  separated  in  the  present  period.  4.  Prof.  Huxley  adduces  many  such 
examples  among  the  mammalian  subdivisions  in  the  remaining  portion  of  his  lect- 
ure. 5.  Two  alternatives  ai*e  yet  open  in  the  explanation  of  the  process  of  evolu- 
tion :  since  generalized  types,  which  combine  the  characters  of  higher  and  lower 
groups  of  later  periods,  must  thus  be  superior  to  the  lower,  the  lower  must  (first)  be 
descended  from  such  a  generalized  form  by  degradation ;  or  (second)  not  descended 
from  it  at  all,  but  from  some  lower  contemporaneous  type  by  advance  ;  the  higher 
only  of  the  two  being  derived  from  the  first-mentioned.  The  last  I  suspect  to  be 
a  true  explanation,  as  it  is  in  accordance  with  the  homologous  groups.  This  law 
will  shorten  the  demands  of  paleontologists  for  time,  since,  instead  of  deriving  all 
Reptilia,  Batrachia,  etc.,  from  common  origins,  it  points  to  the  derivation  of  higher 
Reptilia  of  a  higher  order  from  higher  Reptilia  of  a  lower  order,  lower  Reptilia  of 
the  first  from  lower  Reptilia  of  the  second  ;  finally,  the  several  groups  of  the  lowest 
or  most  generalized  order  of  Reptilia  from  a  parallel  series  of  the  class  below,  or 
Batrachia. 


138  GENEPwAL  EYOLUTIOK 

quainted.  And  inasmucli  as  almost  all  groups,  as  genera,  orders, 
etc.,  which  are  held  to  be  distinct,  but  adjacent,  present  certain 
points  of  approximation  to  each  other,  the  almost  daily  discovery 
of  intermediate  forms  gives  us  confidence  to  believe  that  the 
pointings  in  other  cases  will  also  be  realized. 

y.    Of  Transitions. 

The  preceding  statements  were  necessary  to  the  comprehension 
of  the  supposed  mode  of  metamorphosis  or  development  of  the 
various  types  of  living  beings,  or,  in  other  words,  of  the  single 
structural  features  which  define  them. 

As  it  is  evident  that  the  groups  of  highest  rank  have  had  their 
origin  in  remote  ages,  cases  of  transition  from  one  to  the  other  by 
change  of  character  can  not  be  witnessed  at  the  present  day.  We 
therefore  look  to  the  most  nearly  related  divisions,  or  those  of  the 
lowest  rank,  for  evidence  of  such  change. 

It  is  necessary  to  premise  that  embryology  teaches  that  all  the 
species  of  a  given  branch  of  the  animal  kingdom  (e.  g.,  Verte- 
brate, Mollusc,  etc.)  are  quite  identical  in  structural  character  at 
their  first  appearance  on  the  germinal  layer  of  the  yolk  of  the 
parent  Qgg.  It  shows  that  the  character  of  the  respective  groups 
of  high  rank  api^ear  first,  then  those  of  less  grade,  and  last  of  all 
those  structures  which  distinguish  them  as  genera.  But  among 
the  earliest  characters  which  appear  are  those  of  the  species,  and 
some  of  those  of  the  individual. 

We  find  the  characters  of  different  genera  to  bear  the  same  re- 
lation to  each  other  that  we  have  already  seen  in  the  case  of  those 
definitive  of  orders,  etc.  In  a  natural  assemblage  of  related  genera 
we  discover  that  some  are  defined  by  characters  found  only  in  the 
embryonic  stages  of  others,  while  a  second  will  present  a  perma- 
nent condition  of  its  definitive  part,  which  marks  a  more  ad- 
vanced stage  of  that  highest.  In  this  manner  many  stages  of  the 
highest  genus  a2:)pear  to  be  represented  by  permanent  genera  in  all 
natural  groups.  Generally,  however,  this  resmblance  does  not 
involve  an  entire  identity,  there  being  some  other  immaturities 
found  in  the  highest  genus  at  the  time  it  presents  the  character 
preserved  in  permanency  by  the  lower,  which  the  lower  loses. 
Thus  (to  use  a  very  gross  illustration)  a  frog  at  one  stage  of  growth 
has  four  legs  and  a  tail  ;  the  salamander  always  preserves  four 
legs  and  a  tail,  thus  resembling  the  young  frog.  The  latter  is, 
however,  not  a  salamander  at  that  time,  because,  among  other 


ON  THE  HYPOTHESIS   OF  EVOLUTION.  139 

things,  the  skeleton  is  represented  by  cartilage  only,  and  the  sala- 
mander's is  ossified.  This  relation  is  therefore  an  imitation  only, 
and  is  called  inexact  ^parallelism. 

As  we  compare  nearer  and  nearer  relations — i.  e.,  the  genera 
which  present  fewest  points  of  difference — we  find  the  differences 
between  undeveloped  stages  of  the  higher  and  permanent  con- 
ditions of  the  lower  to  grow  fewer  and  fewer,  until  we  find  numer- 
ous instances  where  the  lower  genus  is  exactly  the  same  as  the 
undeveloped  stage  of  the  higher.  This  relation  is  called  that  of 
exact  parallelism. 

It  must  now  be  remembered  that  the  permanence  of  a  charac- 
ter is  what  gives  it  its  value  in  defining  genus,  order,  etc.,  in  the 
eyes  of  the  systematist.  So  long  as  the  condition  is  permanent  no 
transition  can  be  seen  ;  there  is  therefore  no  development.  If  the 
condition  is  transitional,  it  defines  nothing,  and  nothing  is  devel- 
oped ;  at  least,  so  says  the  anti-developmentalist.  It  is  the  old 
story  of  the  settler  and  the  Indian  :  ^^WiJl  you  take  owl  and  I 
take  turkey,  or  I  take  turkey  and  you  owl  ?  " 

If  we  find  a  relation  of  exact  parallelism  to  exist  between  two 
sets  of  species  in  the  condition  of  a  certain  organ,  and  the  differ- 
ence so  expressed  is  the  only  one  which  distinguishes  them  as  sets 
from  each  other — if  that  condition  is  always  the  same  in  each  set 
— we  call  them  two  genera  :  if  in  any  species  the  condition  is  va- 
riable at  maturity,  or  sometimes  the  undeveloped  condition  of  the 
part  is  persistent  and  sometimes  transitory,  the  sets  characterized 
by  this  difference  must  be  united  by  the  systematist,  and  the  whole 
is  called  a  single  genus. 

We  know  numerous  cases  where  different  individuals  of  the 
same  species  present  this  relation  of  exact  parallelism  to  each 
other  ;  and,  as  we  ascribe  common  origin  to  the  individuals  of  a 
species,  we  are  assured  that  the  condition  of  the  inferior  individual 
is,  in  this  case,  simply  one  of  repressed  growth,  or  a  failure  to  ful- 
fill the  course  accomplished  by  the  highest.  Thus,  certain  species 
of  the  salamandrine  genus  Amblystoma  undergo  a  metamorphosis 
involving  several  parts  of  the  osseous  and  circulatory  systems,  etc., 
while  half  grown  ;  others  delay  it  till  fully  grown  ;  one  or  two 
species  remain  indifferently  unchanged  or  changed,  and  breed  in 
either  condition,  while  another  species  breeds  unchanged,  and  has 
never  been  known  to  complete  a  metamorphosis. 

The  nature  of  the  relation  of  exact  parallelism  is  thus  explained 
to  be  that  of  checked  or  advanced  growth  of  individuals  having  a 


140  GENERAL  EVOLUTION. 

common  origin.  The  relation  of  inexact  parallelism  is  readily  ex- 
plained as  follows  :  With  a  case  of  exact  2^arallelism  in  the  mind, 
let  the  repression  producing  the  character  of  form  B  parallelize 
the  latter  with  a  stage  of  form  A  in  which  a  second  part  is  not 
quite  mature  :  we  will  have  a  slight  want  of  correspondence  be- 
tween the  two.  Form  B  will  be  immature  in  but  one  point,  the 
incompleteness  of  A  higher  being  seen  in  two  points.  If  we 
suppose  the  immaturity  to  consist  in  a  repression  at  a  still  earlier 
point  in  the  history  of  the  higher,  the  latter  will  be  undeveloped 
in  other  points  also  :  thus,  the  spike-horned  deer  of  South  Amer- 
ica have  the  horn  of  the  second  year  of  the  North  American  genus. 
They  would  be  generically  identical  with  that  stage  of  the  latter, 
were  it  not  that  these  still  possess  their  milk  dentition  at  two 
years  of  age.  In  the  same  way  the  nature  of  the  parallelisms  seen 
in  higher  groups,  as  orders,  etc.,  may  be  a'  counted  for. 

The  theory  of  homologous  groups  furnishes  important  evidence 
in  favor  of  derivation.  Many  orders  of  animals  (probably  all, 
when  we  come  to  know  them)  are  divisible  into  two  or  more  sec- 
tions, which  I  have  called  homologous.  These  are  series  of  genera 
or  families,  which  differ  from  each  other  by  some  marked  charac- 
ter, but  whose  contained  genera  or  families  differ  from  each  other 
in  the  same  points  of  detail,  and  in  fact  correspond  exactly.  So 
striking  is  this  correspondence  that  were  it  not  for  the  general  and 
common  character  separating  the  homologous  series,  they  would 
be  regarded  as  the  same,  each  to  each.  Now,  it  is  remarkable  that, 
where  studied,  the  difference  common  to  all  the  terms  of  two  ho- 
mologous groups  is  found  to  be  one  of  inexact  parallelism,  which 
has  been  shown  above  to  be  evidence  of  descent.  Homologous 
groups  always  occupy  different  geographical  areas  on  the  earth's 
surface,  and  their  relation  is  precisely  that  which  holds  between 
successive  groups  of  life  in  the  periods  of  geologic  time.* 

In  a  word,  we  learn  from  this  source  that  distinct  geologic 
epochs  co-exist  at  the  same  time  on  the  earth.  I  have  been  forced 
to  this  conclusion  f  by  a  study  of  the  structure  of  terrestrial  life, 
and  it  has  been  remarkably  confirmed  by  the  results  of  recent 
deep-sea  dredgings  made  by  the  United  States  Coast  Survey  in  the 
Gulf  Stream,  and  by  the  British  naturalists  in  the  North  Atlantic. 
These  have  brought  to  light  types  of  Tertiary  life,  and  of  even 

*  The  extinct  family  of  the  Nimravidas,  which  is  homologous  with  the  existing 
family  of  Felidae,  has  been  discovered  since  this  was  written.     (Ed.  1886.) 
f  "  Origin  of  Genera,"  pp.  70,  77,  79. 


ON  THE  HYPOTHESIS   OF  EYOLUTIOK  141 

the  still  more  ancient  Cretaceous  periods,  living  at  the  present 
day.*  That  this  discovery  invalidates  in  any  wise  the  conclusions 
of  geology  respecting  lapse  of  time  is  an  unwarranted  assumption 
that  some  are  forward  to  make.  If  it  changes  the  views  of  some 
respecting  the  parallelism  or  co-existence  of  faunas  in  different 
regions  of  the  earth,  it  is  only  the  anti-developmentalists  whose 
position  must  be  changed. 

For,  if  we  find  distinct  geologic  faunae,  or  epochs  defined  by 
faunae,  co-existing  during  the  present  period,  and  fading  or  merg- 
ing into  one  another  as  they  do  at  their  geographical  boundaries, 
it  is  proof  positive  that  the  geologic  epochs  and  periods  of  past 
ages  had  in  like  manner  no  trenchant  boundaries,  but  also  passed 
the  one  into  the  other.  The  assumption  that  the  apparent  inter- 
ruptions are  the  result  of  transfer  of  life  rather  than  destruction, 
or  of  want  of  opportunities  of  preservation,  is  no  doubt  the  true 

one. 

8.  Rationale  of  Development. 

a.  In  Characters  of  Higher  Groups. — It  is  evident  in  the  case 
of  the  species  in  which  there  is  an  irregularity  in  the  time  of  com- 
pletion of  metamorphosis,  that  some  individuals  traverse  a  longer 
developmental  line  than  those  which  remain  more  or  less  incom- 
plete. As  both  accomplish  growth  in  the  same  length  of  time,  it 
is  obvious  that  it  proceeds  with  greater  rapidity  in  one  sense  in 
that  which  accomplishes  most ;  its  growth  is  said  to  be  accelerated. 
This  phenomenon  is  especially  common  among  insects,  where  the 
females  of  perfect  males  are  sometimes  larvae  or  nearly  so,  or  pupae, 
or  lack  wings  or  some  character  of  final  development.  Quite  as 
frequently,  some  males  assume  characters  in  advance  of  others, 
sometimes  in  connection  with  a  peculiar  geographical  range. 

In  cases  of  exact  parallelism  we  reasonably  suppose  the  cause 
to  be  the  same,  since  the  conditions  are  identical,  as  has  been 
shown  ;  that  is,  the  higher  conditions  have  been  produced  by  a 
crowding  back  of  the  earlier  characters  and  an  acceleration  of 
growth,  so  that  a  given  succession  in  order  of  advance  has  extended 
over  a  longer  range  of  growth  than  its  predecessor  in  the  same  al- 
lotted time.  That  allotted  time  is  the  period  before  maturity  and 
reproduction,  and  it  is  evident  that  as  fast  as  modifications  or 
characters  should  be  assumed  sufficiently  in  advance  of  that  pe- 
riod, so  certainly  would  they  be  conferred  upon  the  offspring  by 

*  Most  of  the  deep-sea  forms  are,  however,  degenerate  forms  of  existing  orders. 
(Ed.  1886.) 


14:2  GENERAL  EVOLUTION. 

reproduction.  The  acceleration  in  the  assumption  of  a  character, 
progressing  more  rapidly  than  the  same  in  another  character,  must 
soon  produce^  in  a  type  whose  stages  were  once  the  exact  parallel 
of  a  permanent  lower  form,  the  condition  of  inexact  parallelism. 
As  all  the  more  comprehensive  groups  present  this  relation  to  each 
other,  we  are  compelled  to  believe  that  acceleration  has  been  the 
principle  of  their  successive  evolution  during  the  long  ages  of  ge- 
ologic time. 

Each  type  has,  however,  its  day  of  supremacy  and  perfection 
of  organism,  and  a  retrogression  in  these  respects  has  succeeded. 
This  has  no  doubt  followed  a  law  the  reverse  of  acceleration,  which 
has  been  called  retardation.  By  the  increasing  slowness  of  the 
growth  of  the  individuals  of  a  genus,  and  later  and  later  assump- 
tion of  the  characters  of  the  latter,  they  would  be  successively  lost. 

To  what  power  shall  we  ascribe  this  acceleration,  by  which  the 
first  beginnings  of  structure  have  accumulated  to  themselves 
through  the  long  geologic  ages  complication  and  power,  till  from 
the  germ  that  was  scarcely  born  into  a  sand-lance,  a  human  being 
climbed  the  complete  scale,  and  stood  easily  the  chief  of  the 
whole  ? 

In  the  cases  of  species,  where  some  individuals  develop  farther 
than  others,  we  say  the  former  possess  more  growth-force,  or 
*'  vigor,"  than  the  latter.  We  may  therefore  say  that  higher  types 
of  structure  possess  more  "vigor"  than  the  lower.  This,  how- 
ever, we  do  not  know  to  be  true,  nor  can  we  readily  find  means  to 
demonstrate  it. 

The  food  which  is  taken  by  an  adult  animal  is  either  assimi- 
lated, to  be  consumed  in  immediate  activity  of  some  kind,  or 
stored  for  future  use,  and  the  excess  is  rejected  from  the  body. 
We  have  no  reason  to  suppose  that  the  same  kind  of  material 
could  be  made  to  subserve  the  production  of  force  by  any  other 
means  than  that  furnished  by  a  living  animal  organism.  The  ma- 
terial from  which  this  organism  is  constructed  is  derived  first  from 
the  parent,  and  afterward  from  the  food,  etc.,  assimilated  by  the 
individual  itself  so  long  as  growth  continues.  As  it  is  the  activity 
of  assimilation  directed  to  a  special  end  during  this  latter  period 
which  we  suppose  to  be  increased  in  accelerated  develojoment,  the 
acceleration  is  evidently  not  brought  about  by  increased  facilities 
for  obtaining  the  means  of  life  which  the  same  individual  possesses 
as  an  adult.  That  it  is  not  in  consequence  of  such  increased  fa- 
cilities possessed  by  its  parents  over  those  of  the  type  preceding  it 


ON  THE   HYPOTHESIS   OF  EVOLUTION".  143 

seems  equally  improbable  when  we  consider  that  the  characters  in 
which  the  parent's  advance  has  appeared  are  rarely  of  a  nature  to 
increase  those  facilities. 

The  nearest  approach  to  an  explanation  that  can  be  offered 
appears  to  be  somewhat  in  the  following  direction  : 

There  is  every  reason  to  believe  that  the  character  of  the 
atmosphere  has  gradually  changed  during  geologic  time,  and  that 
various  constituents  of  the  mixture  have  been  successively  re- 
moved from  it,  and  been  stored  in  the  solid  material  of  the 
earth's  crust  in  a  state  of  combination.  Geological  chemistry  has 
shown  that  the  cooling  of  the  earth  has  been  accompanied  by  the 
j)recipitation  of  many  substances  only  gaseous  at  high  tempera- 
tures. Hydrochloric  and  sulphuric  acids  have  been  transferred 
to  mineral  deposits  or  aqueous  solutions.  The  removal  of  carbonic- 
acid  gas  and  the  vapor  of  water  has  been  a  process  of  much  slower 
progress,  and  after  the  expiration  of  all  the  ages  a  proportion  of 
both  yet  remains.  Evidence  of  the  abundance  of  the  former  in 
the  earliest  periods  is  seen  in  the  vast  deposits  of  limestone  rock  ; 
later,  in  the  prodigious  quantities  of  shells  which  have  been 
elaborated  from  the  same  in  solution.  Proof  of  its  abundance 
in  the  atmosphere  in  later  periods  is  seen  in  the  extensive  de- 
posits of  coal  of  the  Carboniferous,  Triassic,  and  Jurassic  periods. 
If  the  most  luxuriant  vegetation  of  the  present  day  takes  but  fifty 
tons  of  carbon  from  the  atmosphere  in  a  century,  per  acre,  thus 
producing  a  layer  over  that  extent  of  less  than  a  third  of  an  inch 
in  thickness,  what  amount  of  carbon  must  be  abstracted  in  order 
to  produce  strata  of  thirty-five  feet  in  depth  ?  No  doubt  it  occu- 
pied a  long  period,  but  the  atmosphere,  thus  deprived  of  a  large 
proportion  of  carbonic  acid,  would  in  subsequent  periods  undoubt- 
edly possess  an  improved  capacity  for  the  support  of  animal  life. 

The  successively  higher  degree  of  oxidization  of  the  blood  in 
the  organs  designed  for  that  function,  whether  performing  it  in 
water  or  air,  would  certainly  accelerate  the  performances  of  all 
the  vital  functions,  and  among  others  that  of  growth.  Thus  it 
may  be  that  acceleration  can  be  accounted  for,  and  the  process  of 
the  development  of  the  orders  and  sundry  lesser  groups  of  the 
Vertebrate  kingdom  indicated  ;  for,  as  already  pointed  out,  the 
definitions  of  such  are  radically  placed  in  the  different  structures 
of  the  organs  which  aerate  the  blood  and  distribute  it  to  its 
various  destinations. 

But  the  great  question.  What  determined  the  direction  of  this 


144  GENERAL  EYOLUTIOK 

acceleration  ?  remains  unanswered.  One  can  not  understand  why 
more  highly  oxidized  blood  should  hasten  the  growth  of  j)artition 
of  the  ventricle  of  the  heart  in  the  serpent,  the  more  perfectly  to 
separate  the  aerated  from  the  impure  fluid  ;  nor  can  we  see  why  a 
more  perfectly  constructed  circulatory  system,  sending  purer 
blood  to  the  brain,  should  direct  accelerated  growth  to  the  cere- 
bellum or  cerebral  hemispheres  in  the  crocodile. 

h.  In  Characters  of  the  Specific  Kind. — Some  of  the  charac- 
ters usually  placed  in  the  specific  category  have  been  shown  to  be 
the  same  in  kind  as  those  of  higher  categories.  The  majority  are, 
however,  of  a  different  kind,  and  have  been  discussed  several 
pages  back. 

The  cause  of  the  origin  of  these  characters  is  shrouded  in  as 
much  mystery  as  that  of  those  which  have  occupied  the  pages  im- 
mediately preceding.  As  in  that  case,  we  have  to  assume,  as 
Darwin  has  done,  a  tendency  in  Nature  to  their  production. 
This  is  what  he  terms  ^^the  principle  of  variation."  Against  an 
unlimited  variation  the  great  law  of  heredity  or  atavism  has  ever 
been  opposed,  as  a  conservator  and  multiplier  of  type.  This 
principle  is  exemplified  in  the  fact  that  like  produces  like — that 
children  are  like  their  parents,  frequently  even  in  minutiae.  It 
may  be  compared  to  habit  in  metaphysical  matters,  or  to  that 
singular  love  of  time  or  rhythm  seen  in  man  and  lower  animals, 
in  both  of  which  the  tendency  is  to  repeat  in  continual  cycles  a 
motion  or  state  of  the  mind  or  sense. 

Further,  only  a  proportion  of  the  lines  of  variation  is  supposed 
to  have  been  perpetuated,  and  the  extinction  of  intermediate 
forms,  as  already  stated,  has  left  isolated  groups  or  species. 

The  effective  cause  of  these  extinctions  is  stated  by  Darwin  to 
have  been  a  "natural  selection" — a  proposition  which  distin- 
guishes his  theory  from  other  development  hypotheses,  and  w^hich 
is  stated  in  brief  by  the  expression,  "the  survival  of  the  fit- 
test." Its  meaning  is  this  :  that  those  characters  appearing  as 
results  of  this  spontaneous  variation  which  are  little  adapted  to 
the  conflict  for  subsistence,  with  the  nature  of  the  supply,  or 
with  rivals  in  its  pursuit,  dwindle  and  are  sooner  or  later  ex- 
tirpated ;  while  those  which  are  adapted  to  their  surroundings, 
and  favored  in  the  struggle  for  means  of  life  and  increase,  pre- 
dominate, and  ultimately  become  the  centers  of  new  variation. 
"I  am  convinced,"  says  Darwin,  "that  natural  selection  has 
been  the  main,  but  not  exclusive,  means  of  modification." 


ON  THE   HYPOTHESIS   OF  EVOLUTION.  145 

That  it  has  been  to  a  large  extent  the  means  of  preservation  of 
those  structures  known  as  specific,  must,  I  think,  be  admitted. 
They  are  related  to  their  peculiar  surroundings  very  closely,  and 
are  therefore  more  likely  to  exist  under  their  influence.  Thus,  if 
a  given  genus  extends  its  range  over  a  continent,  it  is  usually 
found  to  be  represented  by  peculiar  species — one  in  a  maritime 
division,  another  in  the  desert,  others  in  the  forest,  in  the  swamp 
or  the  elevated  areas  of  the  region.  The  wonderful  interdepend- 
ence shown  by  Darwin  to  exist  between  insects  and  plants  in  the 
fertilization  of  the  latter,  or  between  animals  and  their  food- 
plants,  would  almost  induce  one  to  believe  that  it  were  the  true 
expression  of  the  whole  law  of  development. 

But  the  following  are  serious  objections  to  its  universal  appli- 
cation : 

First :  The  characters  of  the  higher  groups,  from  genera  up, 
are  rarely  of  a  character  to  fit  their  possessors  especially  for  sur- 
rounding circumstances ;  that  is,  the  differences  which  separate 
genus  from  genus,  order  from  order,  etc.,  in  the  ascending  scale 
of  each,  do  not  seem  to  present  a  superior  adaptation  to  surround- 
ing circumstances  in  the  higher  genus  to  that  seen  in  the  lower 
genus,  etc.  Hence,  superior  adaptation  could  scarcely  have 
caused  their  selection  above  other  forms  not  existing.  Or,  in 
other  words,  the  very  differences  in  structure  which  indicate  suc- 
cessional  relation,  or  which  measure  the  steps  of  progress,  seem  to 
be  equally  well  fitted  for  their  surroundings. 

Second  :  The  higher  groups,  as  orders,  classes,  etc.,  have  been 
in  each  geologic  period  alike  distributed  over  the  whole  earth, 
under  all  the  varied  circumstances  offered  by  climate  and  food. 
Their  characters  do  not  seem  to  have  been  modified  in  reference 
to  these.  Species,  and  often  genera,  are,  on  the  other  hand, 
eminently  restricted  according  to  climate,  and  consequently  vege- 
table and  animal  food. 

The  law  of  development  which  we  seek  is  indeed  not  that 
which  preserves  the  higher  forms  and  rejects  the  lower  after  their 
creation,  but  that  which  explains  why  higher  forms  were  created 
at  all.  Why  in  the  results  of  a  creation  we  see  any  relation  of 
higher  and  lower,  and  not  rather  a  world  of  distinct  types,  each 
perfectly  adapted  to  its  situation,  but  none  properly  higher  than 
another  in  an  ascending  scale,  is  the  primary  question.  Given 
the  principle  of  advance,  then  natural  selection  has  no  doubt 
modified  the  details;  but  in  the  successive  advances  we  can 
10 


146  GENERAL  EVOLUTION. 

scarcely  believe  such  a  principle  to  be  influential.  We  look 
rather  upon  a  progress  as  the  result  of  the  expenditure  of  some 
force  fore-arranged  for  that  end. 

It  may  become,  then,  a  question  whether  in  characters  of  high 
grade  the  habit  or  use  is  not  rather  the  result  of  the  acquisition  of 
the  structure  than  the  structure  the  result  of  the  encouragement 
offered  to  its  assumed  beginnings  by  use,  or  by  liberal  nutrition 
derived  from  the  increasingly  superior  advantages  it  offers. 

€.  The  Physical  Origin  of  Man. 

If  the  hypothesis  here  maintained  be  true,  man  is  the  de- 
scendant of  some  2^re-existent  generic  type,  the  which,  if  it  were 
now  living,  we  would  probably  call  an  ape. 

Man  and  the  chimpanzee  were  in  Linnseus's  system  only  two 
species  of  the  same  genus,  but  a  truer  anatomy  places  them  in 
separate  genera  and  distinct  families.  There  is  no  doubt,  how- 
ever, that  Cuvier  went  much  too  far  when  he  proposed  to  con- 
sider Homo  as  the  representative  of  an  order  distinct  from  the 
Quadrumana,  under  the  name  of  Bimana.  The  structural  differ- 
ences will  not  bear  any  such  inter23retation,  and  have  not  the 
same  value  as  those  distinguishing  the  orders  of  Mammalia ;  as, 
for  instance,  between  Carnivora  and  bats,  or  the  cloven-footed  ani- 
mals and  the  rodents,  or  rodents  and  edentates.  The  differences 
between  man  and  the  chimpanzee  are,  as  Huxley  well  puts  it, 
much  less  than  those  between  the  chimpanzee  and  lower  Quadru- 
mana, as  lemurs,  etc.  In  fact,  man  is  the  type  of  a  family, 
Hominidae,  of  the  order  Quadrumana,  as  indicated  by  the  charac- 
ters of  the  dentition,  extremities,  brain,  etc.  The  reader  who 
may  have  any  doubts  on  this  score  may  read  the  dissections  of 
Geoffroy  St.  Hilaire,  made  in  1856,  before  the  issue  of  Darwin's 
'•'Origin  of  Species."  He  informs  us  that  the  brain  of  man  is 
nearer  in  structure  to  that  of  the  orang  than  the  orang's  is  to 
that  of  the  South  American  howler,  and  that  the  orang  and 
howler  are  more  nearly  related  in  this  regard  than  are  the  howler 
and  the  marmoset. 

The  modifications  presented  by  man  have,  then,  resulted  from 
an  acceleration  in  development  in  some  respects,  and  retardation 
perhaps  in  others.  But  nntil  the  combination  now  characteristic 
of  the  genus  Homo  was  attained,  the  being  could  not  properly  be 
called  man. 

And  here  it  must  be  observed  that  as  an  organic  type  is  char- 


ON   THE   HYPOTHESIS   OF  EVOLUTION.  147 

acterized  by  the  co-existence  of  a  number  of  peculiarities  which 
have  been  developed  independently  of  each  other,  its  distinctive 
features  and  striking  functions  are  not  exhibited  until  that  co- 
existence is  attained  which  is  necessary  for  these  ends. 

Hence,  the  characters  of  the  human  genus  were  probably  de- 
veloped successively  ;  but  few  of  the  indications  of  human  superi- 
ority appeared  until  the  combination  was  accomplished.  Let  the 
opposable  thumb  be  first  perfected,  but  of  what  use  would  it  be 
in  human  affairs  without  a  mind  to  direct  ?  And  of  what  use  a 
mind  without  speech  to  unlock  it  ?  xind  speech  could  not  be 
possible  though  all  the  muscles  of  the  larynx  but  one  were  devel- 
oj^ed,  or  but  a  slight  abnormal  convexity  in  one  pair  of  cartilages 
remained. 

It  would  be  an  objection  of  little  weight  could  it  be  truly 
urged  that  there  have  as  yet  no  remains  of  ape-like  men  been  dis- 
covered, for  we  have  frequently  been  called  upon  in  the  course  of 
paleontological  discovery  to  bridge  greater  gaps  than  this,  and 
greater  remain,  which  we  expect  to  fill.  But  we  have  ape-like 
characters  exhibited  by  more  than  one  race  of  men  yet  existing. 

But  the  remains  of  that  being  which  is  supposed  to  have  been 
the  progenitor  of  man  may  have  been  discovered  a  short  time  since 
in  the  cave  of  Naulette,  Belgium,  with  the  bones  of  the  extinct 
rhinoceros  and  elephant. 

We  all  admit  the  existence  of  higher  and  lower  races,  the  latter 
being  those  which  we  now  find  to  present  greater  or  less  approxi- 
mations to  the  apes.  The  peculiar  structural  characters  that  be- 
long to  the  negro  in  his  most  typical  form  are  of  that  kind,  how- 
ever great  may  be  the  distance  of  his  remove  therefrom.  The 
flattening  of  the  nose  and  prolongation  of  the  jaws  constitute  such 
a  resemblance  ;  so  are  the  deficiency  of  the  calf  of  the  leg,  and  the 
obliquity  of  the  pelvis,  which  approaches  more  the  horizontal  po- 
sition than  it  does  in  the  Caucasian.  The  investigations  made  at 
Washington  during  the  war  with  reference  to  the  physical  charac- 
teristics of  the  soldiers  show  that  the  arms  of  the  negro  are  from 
one  to  two  inches  longer  than  those  of  the  whites  :  another  ap- 
proximation to  the  ape.  In  fact,  this  race  is  a  species  of  the 
genus  Homo,  as  distinct  in  character  from  the  Caucasian  as  those 
we  are  accustomed  to  recognize  in  other  departments  of  the  ani- 
mal kingdom  ;  but  he  is  not  distinct  by  isolation,  since  intermedi- 
ate forms  between  him  and  the  other  species  can  be  abundantly 
found. 


148  GENERAL  EVOLUTION. 

And  here  let  it  be  particularly  observed  that  two  of  the  most 
prominent  characters  of  the  negro  are  those  of  immature  stages  of 
the  Indo-European  race  in  its  characteristic  types.  The  deficient 
calf  is  the  character  of  infants  at  a  very  early  stage  ;  but,  what  is 
more  important,  the  flattened  bridge  of  the  nose  and  shortened 
nasal  cartilages  are  universally  immature  conditions  of  the  same 
parts  in  the  Indo-European.  Any  one  may  convince  himself  of 
that  by  examining  the  physiognomies  of  infants.  In  some  races — 
e.  g.,  the  Slavic — this  undeveloped  character  persists  later  than  in 
some  others.  The  Greek  nose,  with  its  elevated  bridge,  coincides 
not  only  with  assthetic  beauty,  but  with  developmental  perfection. 

This  is,  however,  only  ^^  inexact  parallelism,"  as  the  charac- 
ters of  the  hair,  etc.,  can  not  be  ex^^lained  on  this  principle  among 
existing  races.  The  embryonic  characters  mentioned  are  probably 
a  remnant  of  those  characteristic  of  the  primordial  race  or  species. 

.But  the  man  of  Naulette,  if  he  be  not  a  monstrosity,  is  a  still 
more  distinct  and  ape-like  species.  The  chin,  that  marked  char- 
acter of  other  species  of  men,  is  totally  wanting,  and  the  dentition 
is  quite  approximate  to  the  man-like  apes,  and  different  from  that 
of  modern  men.  The  form  is  very  massive,  as  in  apes.  That  he 
was  not  abnormal  is  rendered  probable  by  approximate  characters 
seen  in  a  jaw  from  the  cave  of  Puy-sur-Aube,  and  less  marked  in 
the  lowest  races  of  Australia  and  New  Caledonia. 

As  to  the  single  or  multiple  origin  of  man,  science  as  yet  fur- 
nishes no  answer.  It  is  very  probable  that,  in  many  cases,  the 
species  of  one  genus  have  descended  from  corresponding  species  of 
another  by  change  of  generic  characters  only.  It  is  a  remarkable 
fact  that  the  orang  possesses  the  peculiarly  developed  malar  bones 
and  the  copper  color  characteristic  of  the  Mongolian  inhabitants 
of  the  regions  in  which  this  animal  is  found,  while  the  gorilla  ex- 
hibits the  prognathic  jaws  and  black  hue  of  the  African  races  near 
whom  he  dwells.  This  kind  of  geographical  imitation  is  very 
common  in  the  animal  kingdom. 

II.    METAPHYSICAL   EVOLUTIOIT. 

It  is  infinitely  improbable  that  a  being  endowed  with  such  ca- 
pacities for  gradual  progress,  as  man  has  exhibited,  should  have 
been  full-fledged  in  accomplishments  at  the  moment  when  he 
could  first  claim  his  high  title,  and  abandon  that  of  his  simian 
ancestors.  We  are,  therefore,  required  to  admit  the  growth  ot 
human  intelligence  from  a  primitive  state  of  inactivity  and  abso- 


ON  THE   HYPOTHESIS   OF  EVOLUTION.  149 

lute  ignorance  ;  including  the  development  of  one  important  mode 
of  its  expression — speech ;  as  well  as  that  of  the  moral  qualities, 
and  of  man's  social  system — the  form  in  which  his  ideas  of  moral- 
ity are  first  displayed. 

The  expression  '* evolution  of  morality"  need  not  offend,  for 
the  question  in  regard  to  the  laws  of  this  evolution  is  the  really 
important  part  of  the  discussion,  and  it  is  to  the  opposing  views 
on  this  point  that  the  most  serious  interest  attaches. 

a.  Development  of  Intelligence, 

If  the  brain  is  the  organ  of  mind,  we  may  be  surprised  to  find 
that  the  brain  of  the  intelligent  man  scarcely  differs  in  structure 
from  that  of  the  ape.  Whence,  then,  the  difference  of  power? 
Though  no  one  will  now  deny  that  many  of  the  Mammalia  are 
capable  of  reasoning  upon  observed  facts,  yet  how  greatly  the  re- 
sults of  this  capacity  differ  in  number  and  importance  from  those 
achieved  by  human  intelligence  !  Like  water  at  the  temperatures 
of  50°  and  53°,  where  we  perceive  no  difference  in  essential  char- 
acter, so  between  the  brains  of  the  lower  and  higher  monkeys  no 
difference  of  function  or  of  intelligence  is  perceptible.  But  what 
a  difference  do  the  two  degrees  of  temperature  from  33°  to  31° 
produce  in  water  !  In  like  manner  the  difference  between  the 
brain  of  the  higher  ape  and  that  of  man  is  accompanied  by  a  dif- 
ference in  function  and  power,  on  which  man's  earthly  destiny 
depends.  In  development,  as  with  the  water,  so  with  the  higher 
ape  ;  some  Rubicon  has  been  crossed,  some  floodgate  has  been 
opened,  which  marks  one  of  Nature's  great  transitions,  such  as 
have  been  called  ** expression-points"  of  progress. 

What  point  of  progress  in  such  a  history  would  account  for 
this  accession  of  the  powers  of  the  human  intelligence  ?  It  has 
been  answered,  with  considerable  confidence — the  power  of  speech. 
Let  us  picture  man  without  speech.  Each  generation  would  learn 
nothing  from  its  predecessors.  Whatever  originality  or  observa- 
tion might  yield  to  a  man  would  die  with  him.  Each  intellectual 
life  would  begin  where  every  other  life  began,  and  would  end  at  a 
point  only  differing  with  its  original  capacity.  Concert  of  action, 
by  which  man's  power  over  the  material  world  is  maintained, 
would  not  exceed,  if  it  equaled,  that  which  is  seen  among  the 
bees  ;  and  the  material  results  of  his  labors  would  not  extend  be- 
yond securing  the  means  of  life  and  the  employment  of  the  sim- 
plest modes  of  defense  and  attack. 


150  GENERAL  EVOLUTION. 

The  first  men,  therefore,  are  looked  upon  by  tho  develop- 
mentalists  as  extremely  embryonic  in  all  that  characterizes  hu- 
manity, and  they  appeal  to  the  facts  of  history  in  support  of  this 
yiew.  If  they  do  not  derive  much  assistance  from  written  his- 
tory, evidence  is  found  in  the  more  enduring  relics  of  human 
handiwork. 

The  opposing  view  is,  that  the  races  which  present  or  have 
presented  this  condition  of  inferiority  or  savagery  have  reached  it 
by  a  process  of  degradation  from  a  higher  state — as  some  believe, 
through  moral  delinquency.  This  position  may  be  true  in  certain 
cases,  which  represent  perhaps  a  condition  of  senility,  but  in  gen- 
eral we  believe  that  savagery  was  the  condition  of  the  first  man, 
which  has  in  some  races  continued  to  the  present  day. 

/?.  Evidence  from  ArchcBology. 

As  the  object  of  the  present  essay  is  not  to  examine  fully  into 
the  evidences  for  the  theories  of  evolution  here  stated,  but  rather 
to  give  a  sketch  of  such  theories  and  their  connection,  a  few  facts 
only  will  be  noticed. 

Im'provement  in  the  Use  of  Materials. — As  is  well  known,  the 
remains  of  human  handiwork  of  the  earliest  periods  consist  of 
nothing  but  rude  implements  of  stone  and  bone,  useful  only  in 
procuring  food  and  preparing  it  for  use.  Even  when  enterprise 
extended  beyond  the  ordinary  routine,  it  was  restrained  by  the 
want  of  proper  instruments.  Knives  and  other  cutting  imple- 
ments of  flint  still  attest  the  skill  of  the  early  races  of  men  from 
Java  to  the  Cape  of  Good  Hope,  from  Egypt  to  Ireland,  and 
through  North  and  South  America.  Hatchets,  spear-heads  and 
ornaments  of  serpentine,  granite,  silex,  clay  slates,  and  all  other 
suitable  rock  materials,  are  found  to  have  been  used  by  the  first 
men,  to  the  exclusion  of  metals,  in  most  of  the  regions  of  the 
earth. 

Later,  the  probably  accidental  discovery  of  the  superiority  of 
some  of  the  metals  resulted  in  the  substitution  of  them  for  stone 
as  a  material  for  cutting  implements.  Copper — the  only  metal 
which,  while  malleable,  is  hard  enough  to  bear  an  imperfect  edge 
— was  used  by  succeeding  races  in  the  Old  World  and  the  New. 
Implements  of  this  material  are  found  scattered  over  extensive 
regions.  So  desirable,  however,  did  the  hardening  of  the  material 
appear  for  the  improvement  of  the  cutting  Q^ge,  that  combinations 
with  other  metals  were  sought  for  and  discovered.    The  alloy  with 


ON"   THE  HYPOTHESIS   OF  EVOLUTION.  151 

tin,  forming  bronze  and  brass,  was  discovered  and  used  in  Enrojie, 
while  that  with  silver  appears  to  have  been  most  readily  produced 
in  America,  and  was  consequently  used  by  the  Peruvians  and  other 
nations. 

The  discovery  of  the  modes  of  reducing  iron  ores  placed  in 
the  hands  of  man  the  best  material  for  bringing  to  a  shape 
convenient  for  his  needs  the  raw  material  of  the  world.  All  im- 
provements in  this  direction  made  since  that  time  have  been  in 
the  quality  of  iron  itself,  and  not  through  the  introduction  of  any 
new  metal. 

The  prevalent  phenomena  of  any  given  period  are  those  which 
give  it  its  character,  and  by  which  we  distinguish  it.  But  this 
fact  does  not  exclude  the  co-existence  of  other  phenomena  belong- 
ing to  prior  or  subsequent  stages.  Thus  during  the  many  stages 
of  human  progress  there  have  been  men  more  or  less  in  advance 
of  the  general  body,  and  their  characteristics  have  given  a  pecul- 
iar stamp  to  the  later  and  higher  condition  of  the  whole.  It 
furnishes  no  objection  to  this  view  that  we  find,  as  might  have 
been  anticijoated,  the  stone,  bronze,  and  iron  periods  overlapping 
one  another,  or  men  of  an  inferior  culture  supplanting  in  some 
cases  a  superior  people.  A  case  of  this  kind  is  seen  in  North 
America,  where  the  existing  *^  Indians,"  stone-men,  have  suc- 
ceeded the  mound-builders,  copper-men.  The  successional  rela- 
tion of  discoveries  is  all  that  it  is  necessary  to  prove,  and  this 
seems  to  be  established. 

The  period  at  which  the  use  of  metallic  implements  was  intro- 
duced is  unknown,  but  Whitney  says  that  the  language  of  the 
Aryans,  the  ancestors  of  all  the  modern  Indo-Europeans,  indicates 
an  acquaintance  with  such  implements,  though  it  is  not  certain 
whether  those  of  iron  are  to  be  included.  The  dispersion  of  the 
daughter  races,  the  Hindoos,  the  Pelasgi,  Teutons,  Celts,  etc., 
could  not,  it  is  thought,  have  taken  j^lace  later  than  3000  b.  c. — 
a  date  seven  hundred  years  prior  to  that  assigned  by  the  old  chro- 
nology to  the  Deluge.  Those  races  co-existed  with  the  Egyptian 
and  Chinese  nations,  already  civilized,  and  as  distinct  from  each 
other  in  feature  as  they  are  now. 

Improvement  in  Architecture. — The  earliest  periods,  then,  were 
characterized  by  the  utmost  simplicity  of  invention  and  construc- 
tion. Later,  the  efforts  for  defense  from  enemies  and  for  architect- 
ural display,  which  have  always  employed  so  much  time  and 
power,  began  to  be  made.     The  megalithic  period  has  left  traces 


152  GENERAL  EVOLUTION. 

over  much  of  the  earth.  The  great  masses  of  stone  piled  on  each 
other  in  the  simplest  form  in  Southern  India,  and  the  circles  of 
stones  planted  on  end  in  England  at  Stonehenge  and  Abury,  and 
in  Peru  at  Sillustani,  are  relics  of  that  period.  More  complex 
are  the  great  Himyaritic  walls  of  Arabia,  the  works  of  the  ances- 
tors of  the  Phoenicians  in  Asia  Minor,  and  the  titanic  workmanship 
of  the  Pelasgi  in  Greece  and  Italy.  In  the  iron  age  we  find  gra- 
nitic hills  shaped  or  excavated  into  temples  ;  as,  for  example, 
everywhere  in  Southern  India.  Near  Madura  the  circumference 
of  an  acropolis-like  hill  is  cut  into  a  series  of  statues  in  high  re- 
lief, of  sixty  feet  in  elevation.  Easter  Island,  composed  of  two 
volcanic  cones,  one  thousand  miles  from  the  west  coast  of  South 
America,  in  the  bosom  of  the  Pacific,  possesses  several  colossi  cut 
from  the  intrusive  basalt,  some  in  high  relief  on  the  face  of  the 
rock,  others  in  detached  blocks  removed  by  human  art  from  their 
original  positions  and  brought  nearer  the  sea-shore. 

Finally,  at  a  more  advanced  stage,  the  more  ornate  and  com- 
plex structures  of  Central  America,  of  Cambodia,  Nineveh  and 
Egypt,  represent  the  period  of  greatest  display  of  architectural  ex- 
penditure. The  same  amount  of  human  force  has  perhaps  never 
been  expended  in  this  direction  since,  though  higher  conceptions 
of  beauty  have  been  developed  in  architecture  with  increasing  in- 
tellectuality. 

Man  has  passed  through  the  block-and-brick  building  period 
of  his  boyhood,  and  should  rise  to  higher  conceptions  of  what  is 
the  true  disposition  of  power  for  "  him  who  builds  for  aye,"  and 
learn  that  *^  spectacle  "  is  often  the  unwilling  friend  of  j^rogress. 

No  traces  of  metallic  implements  have  ever  been  found  in  the 
salt-mines  of  Armenia,  the  turquoise-quarries  in  Arabia,  the  cities 
of  Central  America,  or  the  excavations  for  mica  in  North  Carolina, 
while  the  direct  evidence  points  to  the  conclusion  that  in  those 
places  flint  was  exclusively  used. 

The  simplest  occupations,  as  requiring  the  least  exercise  of 
mind,  are  the  pursuit  of  the  chase  and  the  tending  of  flocks  and 
herds.  Accordingly,  we  find  our  first  parents  engaged  in  these 
occupations.  Cain,  we  are  told,  was,  in  addition,  a  tiller  of  the 
ground.  Agriculture  in  its  simplest  forms  requires  but  little 
more  intelligence  than  the  pursuits  just  mentioned,  though  no 
employment  is  capable  of  higher  development.  If  we  look  at  the 
savage  nations  at  present  occupying  nearly  half  the  land  surface 
of  the  earth,  we  shall  find  many  examples  of  the  former  indus- 


ON   THE   HYPOTHESIS   OF  EVOLUTION.  I53 

trial  condition  of  our  race  preserved  to  the  present  day.  Many 
of  them  had  no  knowledge  of  the  use  of  metals  until  they  ob- 
tained it  from  civilized  men  who  visited  them,  while  their  pur- 
suits were  and  are  those  of  the  chase,  tending  domestic  animals, 
and  rudimental  agriculture. 

7.  Development  of  the  Fine  Arts. 

If  we  look  at  representation  by  drawing  or  sculpture,  we  find 
that  the  efforts  of  the  earliest  races  of  which  we  have  any  knowl- 
edge were  quite  similar  to  those  which  the  untaught  hand  of  in- 
fancy traces  on  its  .slate  or  the  savage  depicts  on  the  rocky  faces 
of  hills.  The  circle  or  triangle  for  the  head  and  body,  and 
straight  lines  for  the  limbs,  have  been  preserved  as  the  first  at- 
tempts of  the  men  of  the  stone  period,  as  they  are  to  this  day  tlie 
sole  representations  of  the  human  form  which  the  North  American 
Indian  places  on  his  buffalo  robe  or  mountain  precipice.  The 
stiff,  barely  outlined  form  of  the  deer,  the  turtle,  etc.,  are  liter- 
ally those  of  the  infancy  of  civilized  man. 

The  first  attempts  at  sculpture  were  marred  by  the  influence 
of  modism.  Thus  the  idols  of  Cohan  and  Palenque,  with  human 
faces  of  some  merit,  are  overloaded  with  absurd  ornament,  and 
deformed  into  frightful  asymmetry,  in  compliance  with  the  de- 
mand of  some  imperious  mode.  In  later  days  we  have  the  stiff, 
conventionalized  figures  of  the  palaces  of  Nineveh  and  the  temples 
of  Egypt,  where  the  representation  of  form  has  somewhat  improved, 
but  is  too  often  distorted  by  false  fashion  or  imitation  of  some 
unnatural  standard,  real  or  artistic.  This  is  distinsfuished  as  the 
day  of  archaic  sculpture,  which  disappeared  with  the  Etruscan 
nation.  So  the  drawings  of  the  child,  when  he  abandons  the 
simple  lines,  are  stiff  and  awkward,  and  but  a  stage  nearer  true 
representation  ;  and  how  often  does  he  repeat  some  peculiarity  or 
absurdity  of  his  own  ! 

The  introduction  of  the  action  and  pose  of  life  into  sculpture 
was  not  known  before  the  early  days  of  Greece,  and  it  was  there 
that  the  art  was  brought  to  perfection.  When  art  rose  from  its 
mediaeval  slumber,  much  the  same  succession  of  development  may 
be  discovered.  First,  the  stiff  figures,  with  straightened  limbs 
and  cylindric  drapery,  found  in  the  old  Northern  churches — then 
the  forms  of  life  that  now  adorn  the  porticoes  and  palaces  of  the 
cities  of  Germanv. 


154  GENERAL  EVOLUTION. 

d.   Rationale  of  the  Development  of  Intelligence. 

The  history  of  material  development  shows  that  the  transition 
from  stage  to  stage  of  development,  experienced  by  the  most  per- 
fect forms  of  animals  and  plants  in  their  growth  from  the  primor- 
dial cell,  is  similar  to  the  succession  of  created  beings  which  the 
geological  epochs  produced.  It  also  shows  that  the  slow  assump- 
tion of  main  characters  in  the  line  of  succession  in  early  geological 
periods  produced  the  condition  of  inferiority,  while  an  increased 
rapidity  of  growth  in  later  days  has  resulted  in  an  attainment  of 
superiority.  It  is  not  to  be  supposed  that  in  ^^acceleration"  the 
period  of  growth  is  shortened  ;  on  the  contrary,  it  continues  the 
same.  Of  two  beings  whose  characters  are  assumed  at  the  same 
rate  of  succession,  that  with  the  quickest  or  shortest  growth  is 
necessarily  inferior.  ^^Acceleration"  means  a  gradual  increase  of 
the  rate  of  assumption  of  successive  characters  in  the  same  period 
of  time.  A  fixed  rate  of  assumption  of  characters,  with  gradual 
increase  in  the  length  of  the  period  of  growth,  would  produce  the 
same  result — viz.,  a  longer  developmental  scale  and  the  attainment 
of  an  advanced  position.  The  first  is  in  part  the  relation  of  sexes 
of  a  species  ;  the  last  of  genera,  and  of  other  types  of  creation.  If 
from  an  observed  relation  of  many  facts  we  derive  a  law,  we  are 
permitted,  when  we  see  in  another  class  of  facts  similar  relations, 
to  suspect  that  a  similar  law  has  operated,  differing  only  in  its  ob- 
jects. We  find  a  marked  resemblance  between  the  facts  of  struct- 
ural progress  in  matter  and  the  phenomena  of  intellectual  and 
spiritual  progress. 

If  the  facts  entering  into  the  categories  enumerated  in  the  pre- 
ceding section  bear  us  out,  we  conclude  that  in  the  beginning  of 
human  history  the  progress  of  the  individual  man  was  very  slow, 
and  that  but  little  was  attained  to  ;  that,  through  the  profitable 
direction  of  human  energy,  means  were  discovered  from  time  to 
time  by  which  the  process  of  individual  development  in  all  meta- 
physical qualities  has  been  accelerated  ;  and  that  up  to  the  pres- 
ent time  the  consequent  advance  of  the  whole  race  has  been  at  an 
increasing  rate  of  progress.  This  is  in  accordance  with  the  gen- 
eral principle,  that  high  development  in  intellectual  things  is 
accomplished  by  rapidity  in  traversing  the  preliminary  stages  of 
inferiority  common  to  all,  while  low  develo^oment  signifies  slug- 
gishness in  that  progress,  and  a  corresi^onding  retention  of  in- 
feriority. 


ON  THE   HYPOTHESIS   OF  EVOLUTION.  155 

How  mucli  meaning  may  we  not  see,  from  this  standpoint, 
in  the  history  of  the  intelligence  of  our  little  ones  !  First  they 
crawl,  they  walk  on  all-fours  ;  when  they  first  assume  the  erect 
position  they  are  generally  speechless,  and  utter  only  inarticulate 
sounds.  When  they  run  about,  stones  and  dirt,  the  objects  that 
first  meet  the  eye,  are  the  delight  of  their  awakening  powers  ;  but 
these  are  all  cast  aside  when  the  boy  obtains  his  first  jackknife. 
Soon,  however,  reading  and  writing  open  a  new  world  to  him  ; 
and,  finally,  as  a  mature  man  he  seizes  the  forces  of  Nature,  and 
steam  and  electricity  do  his  bidding  in  the  active  pursuit  of  power 
for  still  better  and  higher  ends. 

So  with  the  history  of  the  species  :  first,  the  quadrumane ; 
then  the  speaking  man,  whose  humble  industry  was,  however, 
confined  to  the  objects  that  came  first  to  hand,  this  being  the 
** stone  age"  of  i^re-historic  time.  When  the  use  of  metals  was 
discovered,  the  range  of  industries  expanded  wonderfully,  and  the 
*^iron  age  "  saw  many  striking  efforts  of  human  power.  With  the 
introduction  of  letters  it  became  possible  to  record  events  and  ex- 
periences, and  the  spread  of  knowledge  was  thereby  greatly  in- 
creased, and  the  delays  and  mistakes  of  ignorance  correspondingly 
diminished  in  the  fields  of  the  world's  activity. 

From  the  first  we  see  in  history  a  slow  advance  as  knowledge 
gained  by  the  accumulation  of  tradition  and  by  improvements  in 
habit  based  on  experience  ;  but  how  slow  was  this  advance  while 
the  use  of  the  metals  was  still  unknown  !  The  iron  age  brought 
with  it  not  only  new  conveniences,  but  increased  means  of  future 
progress  ;  and  here  we  have  an  acceleration  in  the  rate  of  advance. 
With  the  introduction  of  letters  this  rate  was  increased  manifold, 
and  in  the  application  of  steam  we  have  a  change  equal  in  utility 
to  any  that  has  preceded  it,  and  adding  to  the  possibilities  of  fu- 
ture advance  in  many  directions.  By  it  power,  knowledge,  and 
means  of  happiness  were  to  be  distributed  among  the  many. 

The  uses  to  which  human  intelligence  has  successively  applied 
the  materials  furnished  by  Nature  have  been — first,  subsistence 
and  defense  ;  second,  the  accumulation  of  power  in  the  shape  of  a 
representative  of  that  labor  which  the  use  of  matter  involves — in 
other  words,  the  accumulation  of  wealth.  The  possession  of  this 
power  involves  new  possibilities,  for  opportunity  is  offered  for  the 
special  pursuits  of  knowledge  and  the  assistance  of  the  weak  or 
undeveloped  part  of  mankind  in  its  struggles. 

Thus,  while  the  first  men  possessed  the  power  of  speech,  and 


156  GENERAL  EVOLUTION. 

could  advance  a  little  in  knowledge  through  the  accumulation  of 
the  experiences  of  their  predecessors,  they  possessed  no  means  of 
accumulating  the  power  of  labor,  no  control  over  the  activity  of 
numbers — in  other  words,  no  wealth. 

But  the  accumulation  of  knowledge  finally  brought  this  ad- 
vance about.  The  extraction  and  utilization  of  the  metals,  espe- 
cially iron,  formed  the  most  important  step,  since  labor  was  thus 
facilitated  and  its  productiveness  increased  in  an  incalculable  de- 
gree. We  have  little  evidence  of  the  existence  of  a  medium  of  ex- 
change during  the  first  or  stone  period,  and  no  doubt  barter  was 
the  only  form  of  trade.  Before  the  use  of  metals,  shells  and  other 
objects  were  used  ;  remains  of  money  of  baked  clay  have  been 
found  in  Mexico.  Finally,  though  in  still  ancient  times,  the  pos- 
session of  wealth  in  money  gradually  became  possible  and  more 
common,  and  from  that  day  to  this  avenues  for  reaching  this  stage 
in  social  progress  have  ever  been  opening. 

But  wealth  merely  indicates  a  stage  of  progress,  since  it  is  but 
a  comparative  term.  All  men  could  not  become  rich,  for  in  that 
case  all  would  be  equally  poor.  But  labor  has  a  still  higher  goal ; 
for,  thirdly,  as  capital,  it  constructs  and  employs  machinery, 
which  does  the  work  of  many  hands,  and  thus  cheapens  products, 
which  is  equivalent  in  effect  to  an  accumulation  of  wealth  to  the 
consumer.  And  this  increase  of  power  may  be  used  for  the  intel- 
lectual and  spiritual  advance  of  men,  or,  otherwise,  at  the  will  of 
the  men  thus  favored.  Machinery  places  man  in  the  position  of  a 
creator,  operating  on  Mature  through  an  increased  number  of 
*' secondary  causes." 

Development  of  intelligence  is  seen,  then,  in  the  following 
directions  :  First,  in  the  knowledge  of  facts,  including  science  ; 
second,  in  language  ;  and,  as  consequences  of  these,  the  accumula- 
tion of  power  by  development — first,  of  means  of  subsistence  ;  and, 
second,  of  mechanical  invention  ;  and,  third,  in  the  apprehension 
of  beauty. 

Thus,  we  have  two  terms  to  start  with  in  estimating  the  be- 
ginning of  human  development  in  knowledge  and  power  :  first, 
the  primary  capacities  of  the  human  mind  itself  ;  second,  a  mate- 
rial world,  whose  infinitely  varied  components  are  so  arranged  as 
to  yield  results  to  the  energies  of  that  mind.  For  example,  the 
transition-points  of  vaporization  and  liquefaction  are  so  placed  as 
to  be  within  the  reach  of  man's  agents  ;  their  weights  are  so  fixed 
as  to  accord  with  the  muscular  or  other  forces  which  he  is  able  to 


ON   THE  HYPOTHESIS   OF  EVOLUTION.  157 

exert ;  and  other  living  organizations  are  subject  to  his  conven- 
ience and  rule,  and  not,  as  in  previous  geological  periods,  entirely 
beyond  his  control.  These  two  terms  being  given,  it  is  maintained 
that  the  present  situation  of  the  most  civilized  men  has  been  at- 
tained through  the  operation  of  a  law  of  mutual  action  and  reac- 
tion— a  law  whose  results,  seen  at  the  present  time,  have  depended 
on  the  acceleration  or  retardation  of  its  rate  of  action  ;  which  rate 
has  been  regulated,  according  to  the  degree  in  which  a  third  great 
term,  viz.,  the  law  of  moral  or  (what  is  the  same  thing)  true  re- 
ligious development,  has  been  combined  in  the  plan.  What  it  is 
necessary  to  establish  in  order  to  prove  the  above  hypothesis  is — 

I.  That  in  each  of  the  particulars  above  enumerated  the  devel- 
opment of  the  human  species  is  similar  to  that  of  the  individual 
from  infancy  to  maturity. 

II.  That  from  a  condition  of  subserviency  to  the  laws  of  mat- 
ter, man's  intelligence  enables  him,  by  an  accumulation  of  power, 
to  become  in  a  sense  independent  of  those  laws,  and  to  pursue  a 
course  of  intellectual  and  spiritual  progress. 

III.  That  failure  to  accomplish  a  moral  or  spiritual  develop- 
ment will  again  reduce  him  to  a  subserviency  to  the  laws  of 
matter. 

This  brings  us  to  the  subject  of  moral  development.  And  here 
I  may  be  allowed  to  suggest  that  the  weight  of  the  evidence  is 
opposed  to  the  philosophy,  ^'  falsely  so  called,"  of  necessitarianism, 
which  asserts  that  the  first  two  terms  alone  were  sufficient  to  work 
out  man's  salvation  in  this  world  and  the  next ;  and,  on  the  other 
hand,  to  that  anti-philosophy  which  asserts  that  all  things  in  hu- 
man progress,  intellectual  and  moral,  are  regulated  by  immediate 
divine  interposition  instead  of  through  instrumentalities.  Hence, 
the  subject  divides  itself  at  once  into  two  great  departments — viz., 
that  of  the  development  of  mind  or  intelligence,  and  that  of  the 
development  of  morality. 

That  these  laws  are  distinct  there  can  be  no  doubt,  since  in 
the  individual  man  one  of  them  may  produce  results  without  the 
aid  of  the  other.  Yet  it  can  be  shown  that  each  is  the  most  in- 
valuable aid  and  stimulant  to  the  other,  and  most  favorable  to 
the  rapid  advance  of  the  mind  in  either  direction. 

III.    SPIRITUAL    OR   MORAL   DEVELOPMENT. 

In  examining  this  subject,  we  first  inquire  (Section  a)  whether 
there  is  any  connection  between  physical  and  moral  or  religious 


158  GENERAL  EVOLUTION. 

development ;  then  (/3),  what  indications  of  moral  development 
may  be  derived  from  history.  Finally  (y),  a  correlation  of  the 
results  of  these  inquiries,  with  the  nature  of  the  religious  develop- 
ment in  the  individual,  is  attempted.  Of  course  in  so  stupendous 
an  inquiry  but  a  few  leading  points  can  be  presented  here. 

If  it  be  true  that  the  period  of  human  existence  on  the  earth 
has  seen  a  gradually  increasing  predominance  of  higher  motives 
over  lower  ones  among  the  mass  of  mankind,  and  if  any  parts  of 
our  metaphysical  being  have  been  derived  by  inheritance  from 
pre-existent  beings,  we  are  incited  to  the  inquiry  whether  any  of 
the  moral  qualities  are  included  among  the  latter ;  and  whether 
there  be  any  resemblance  between  moral  and  intellectual  develop- 
ment. 

Thus,  if  there  have  been  a  physical  derivation  from  a  pre- 
existent  genus,  and  an  embryonic  condition  of  those  physical 
characters  which  distinguish  Homo — if  there  has  been  also  an 
embryonic  or  infantile  stage  in  intellectual  qualities — we  are  led 
to  inquire  whether  the  development  of  the  individual  in  moral 
nature  will  furnish  us  with  a  standard  of  estimation  of  the  suc- 
cessive conditions  or  present  relations  of  the  human  species  in 
this  aspect  also. 

a.  Belations  of  Physical  and  Moral  Nature. 

Although,  cmteris  paribus,  men  are  much  alike  in  the  deeper 
qualities  of  their  nature,  there  is  a  range  of  variation  which  is 
best  understood  by  a  consideration  of  the  extremes  of  such  varia- 
tion as  seen  in  men  of  different  latitudes,  and  women  and  chil- 
dren. 

{a)  In  Children. — Youth  is  distinguished  by  a  peculiarity, 
which  no  doubt  depends  upon  an  immature  condition  of  the  nerv- 
ous center  concerned,  which  might  be  called  nervous  impressi- 
bility. It  is  exhibited  in  a  greater  tendency  to  tearfulness,  in 
timidity,  less  mental  endurance,  a  greater  facility  in  acquiring 
knowledge,  and  more  ready  susceptibility  to  the  influence  of 
sights,  sounds,  and  sensations.  In  both  sexes  the  emotional 
nature  predominates  over  the  intelligence  and  judgment.  In 
those  years  the  character  is  said  to  be  in  embryo,  and  theologians, 
in  using  the  phrase,  '*  reaching  years  of  religious  understanding," 
mean  that  in  early  years  the  religious  capacities  undergo  develop- 
ment coincidentally  with  those  of  the  body. 

{h)  In  Women. — If  we  examine  the  metaphysical  characteris- 


ON   THE  HYPOTHESIS   OF   EVOLUTION.  159 

tics  of  women,  we  observe  two  classes  of  traits— namely,  those 
which  are  also  found  in  men,  and  those  which  are  absent  or  but 
weakly  developed  in  men.  Those  of  the  first  class  are  very 
similar  in  essential  nature  to  those  which  men  exhibit  at  an  early 
stage  of  development.  This  may  be  in  some  way  related  to  the 
fact  that  physical  maturity  occurs  earlier  in  women. 

The  gentler  sex  is  characterized  by  a  greater  impressibility, 
often  seen  in  the  influence  exercised  by  a  stronger  character,  as 
well  as  by  music,  color,  or  spectacle  generally ;  warmth  of  emo- 
tion, submission  to  its  influence  rather  than  that  of  logic  ;  ti- 
midity and  irregularity  of  action  in  the  outer  world.  All  these 
qualities  belong  to  the  male  sex,  as  a  general  rule,  at  some  period 
of  life,  though  different  individuals  lose  them  at  very  various 
periods.  Euggedness  and  sternness  may  rarely  be  developed  in 
infancy,  yet  at  some  still  prior  time  they  certainly  do  not  exist  in 
any. 

Probably  most  men  can  recollect  some  early  period  of  their 
lives  when  the  emotional  nature  predominated — a  time  when 
emotion  at  the  sight  of  suffering  was  more  easily  stirred  than  in 
maturer  years.  I  do  not  now  allude  to  the  benevolence  inspired, 
kept  alive,  or  developed  by  the  influence  of  the  Christian  religion 
on  the  heart,  but  rather  to  that  which  belongs  to  the  natural 
man.  Perhaps  all  men  can  recall  a  period  of  youth  when  they 
were  hero-worshipers — when  they  felt  the  need  of  a  stronger  arm, 
and  loved  to  look  up  to  the  powerful  friend  who  could  sympathize 
with  and  aid  them.  This  is  the  ^*  woman  stage  "  of  character  :  in 
a  large  number  of  cases  it  is  early  passed  ;  in  some  it  lasts  longer ; 
while  in  a  very  few  men  it  persists  through  life.  Severe  disciiDline 
and  labor  are  unfavorable  to  its  persistence.  Luxury  preserves  its 
bad  qualities  without  its  good,  while  Christianity  j)reserves  its 
good  elements  without  its  bad. 

It  is  not  designed  to  say  that  woman  in  her  emotional  nature 
does  not  differ  from  the  undeveloped  man.  On  the  contrary, 
though  she  does  not  differ  in  kind,  she  differs  greatly  in  degree, 
for  her  qualities  grow  with  her  growth,  and  exceed  m  poiver  many 
fold  those  exhibited  by  her  companion  at  the  original  point  of 
departure.  Hence,  since  it  might  be  said  that  man  is  the  unde- 
veloped woman,  a  word  of  explanation  will  be  useful.  Embryonic 
types  abound  in  the  fields  of  nature,  but  they  are  not  therefore 
immature  in  the  usual  sense.  Maintaining  the  lower  essential 
quality,  they  yet  exhibit  the  usual  results  of  growth  in  individual 


160  GENERAL  EVOLUTION. 

characters  ;  that  is,  increase  of  strength,  powers  of  support  and 
protection,  size  and  beauty.  In  order  to  maintain  that  the  mas- 
culine character  coincides  with  that  of  the  undeveloped  woman, 
it  would  be  necessary  to  show  that  the  latter  during  her  infancy 
possesses  the  male  characters  predominating — that  is,  unimpressi- 
bility,  judgment,  physical  courage,  and  the  like. 

If  we  look  at  the  second  class  of  female  characters — nameh', 
those  which  are  imperfectly  developed  or  absent  in  men,  and  in 
respect  to  which  man  may  be  called  undeveloped  woman — we 
note  three  prominent  points  :  facility  in  language,  tact  or  finesse, 
and  the  love  of  children.  The  first  two  appear  to  me  to  be  alto- 
gether developed  results  of  ^^impressibility,"  already  considered 
as  an  indication  of  immaturity.  Imagination  is  also  a  quality  of 
impressibility,  and,  associated  with  finesse,  is  apt  to  degenerate 
into  duplicity  and  untruthfulness — a  i^eculiarity  more  natural  to 
women  than  men. 

The  third  quality  is  different.  It  generally  appears  at  a  very 
early  period  of  life.  Who  does  not  know  how  soon  the  little  girl 
selects  the  doll,  and  the  boy  the  toy-horse  or  machine  ?  Here 
man  truly  never  gets  beyond  undeveloped  woman.  Nevertheless, 
^^impressibility"  seems  to  have  a  great  deal  to  do  with  this 
quality  also. 

Thus  the  metaphysical  relation  of  the  sexes  would  appear  to 
be  one  of  inexact  parallelism,  as  defined  in  Section  I.  That  the 
physical  relation  is  a  remote  one  of  the  same  kind,  several  charac- 
ters seem  to  point  out.  The  case  of  the  vocal  organs  will  suffice. 
Their  structure  is  identical  in  both  sexes  in  early  youth,  and  botii 
produce  nearly  similar  sounds.  They  remain  in  this  condition  in 
the  woman,  while  they  undergo  a  metamorjohosis  and  change  both 
in  structure  and  vocal  power  in  the  man.  In  the  same  way,  in 
many  of  the  lower  creation,  the  females  possess  a  majority  of  em- 
bryonic features,  though  not  invariably.  A  common  example  is 
to  be  found  in  the  plumage  of  birds,  where  the  females  and  young 
males  are  often  undistinguishable.*    But  there  are  a  few  points  in 

*  Meehan  states  that  the  upper  limbs  and  stronc^  laterals  in  Coniferge  and  other 
trees  produce  female  flowers  and  cones,  and  the  lower  and  more  interior  branches 
the  male  flowers.  He  calls  the  former  condition  one  of  greater  "  vigor,"  and  the 
latter  one  of  *'  weakness,"  and  argues  that  the  vigorous  condition  of  growth  pro- 
duces females,  and  the  weaker  males.  What  he  points  out,  however,  is  in  harmony 
with  the  position  here  maintained — namely,  that  the  female  characters  include  more 
of  those  which  are  embryonic  in  the  males  than  the  male  characters  include  of  those 


ON  THE  HYPOTHESIS   OF  EVOLUTION.  id 

the  physical  structure  of  man  also  in  which  the  male  condition  is 
the  immature  one.  In  regard  to  structure,  the  point  at  which 
the  relation  between  the  sexes  is  that  of  exact  parallelism,  or 
where  the  mature  condition  of  the  one  sex  accords  with  the  unde- 
veloped condition  of  the  other,  is  when  reproduction  is  no  longer 
accomplished  by  budding  or  gemmation,  but  requires  distinct 
organs.  Metaphysically,  this  relation  is  to  be  found  where  dis- 
tinct individuality  of  the  sexes  first  appears  ;  that  is,  where  we 
pass  from  the  hermaphrodite  to  the  bisexual  condition. 

But  let  us  put  the  whole  interpretation  on  this  partial  unde- 
velopment  of  woman. 

The  types  or  conditions  of  organic  life  which  have  been  the 
most  prominent  in  the  world's  history— the  Ganoids  of  the  first, 
the  Dinosaurs  of  the  second,  and  the  Mammoths  of  the  third 
period— have  generally  died  with  their  day.  The  line  of  succes- 
sion has  not  been  from  them.  The  law  of  anatom.y  and  paleon- 
tology is,  that  we  must  seek  the  point  of  departure  of  the  type 
which  is  to  predominate  in  the  future,  at  lower  stages  on  the  line, 
in  less  decided  forms,  or  in  what,  in  scientific  parlance,  are  called 
generalized  types.  In  the  same  way,  though  the  adults  of  the 
tailless  apes  are  in  a  physical  sense  more  highly  developed  than 
their  young,  yet  the  latter  far  more  closely  resemble  the  human 
species  in  their  large  facial  angle  and  shortened  jaws. 

How  much  significance,  then,  is  added  to  the  law  uttered  by 
Christ ! — ^'Except  ye  become  as  little  children,  ye  can  not  enter 
the  kingdom  of  heaven.'^  Submission  of  will,  loving  trust,  con- 
fiding faith — these  belong  to  the  child  :  how  strange  they  appear 
to  the  executing,  commanding,  reasoning  man  !  Are  they  so 
strange  to  the  woman  ?  We  all  know  the  answer.  Woman  is 
nearer  to  the  point  of  departure  of  that  development  which  out- 
lives time  and  j^eoples  heaven  ;  and  if  man  would  find  it,  he  must 
retrace  his  steps,  regain  something  he  lost  in  youth,  and  join  to 

which  are  embryonic  in  the  female :  the  female  flowers  are  the  product  of  the 
younger  and  more  growing  portions  of  the  tree — that  is,  those  last  produced  (the 
upper  limbs  and  new  branches) — while  the  male  flowers  are  produced  by  the  older 
or  more  mature  portions — that  is,  lower  limbs  or  more  axial  regions.  Further,  we 
are  not  accustomed  to  regard  the  condition  of  rapid  growth  as  that  of  great  vigor 
in  animals,  but  rather  ascribe  that  quality  to  maturity,  after  such  growth  has 
ceased. 

Meehan's  observations  coincide  with  those  of  Thury  and  others  on  the  origin 
of  sexes  in  animals  and  plants,  which  it  appears  to  me  admit  of  a  similar  explana- 
tion. 

11 


102  GENERAL  EVOLUTIOI^. 

the  powers  and  energies  of  his  character  the  suhmission,  love  and 
faith  which  the  new  birth  alone  can  give. 

Thus  the  summing  up  of  the  metaphj'sical  qualities  of  woman 
would  be  thus  expressed  :  In  the  emotional  world,  man's  superior  ; 
in  the  moral  world,  his  equal ;  in  the  laboring  world,  his  inferior. 

There  are,  however,  vast  differences  in  women  in  respect  to 
the  number  of  masculine  traits  they  may  have  assumed  before  be- 
ing determined  into  their  own  special  development.  Woman  also, 
under  the  influence  of  necessity,  in  later  years  of  life,  may  add 
more  or  less  to  those  qualities  in  her  which  are  fully  developed  in 
the  man. 

The  relation  of  these  facts  to  the  principles  stated  as  the  two 
opposing  laws  of  development  is,  it  apjDcars  to  me,  to  be  exjolained 
thus  :  First,  that  woman's  most  inherent  peculiarities  are  not  the 
result  of  the  external  circumstances  with  which  she  has  been 
j)laced  in  contact,  as  the  conflict  theory  would  indicate.  Such 
circumstances  are  said  to  be  her  involuntary  subserviency  to  the 
physically  more  powerful  man,  and  the  effect  of  a  compulsory 
mode  of  life  in  preventing  her  from  attaining  a  position  of  equali- 
ty in  the  activities  of  the  world.  Second,  that  they  are  the  result 
of  the  different  distributions  of  qualities  as  already  indicated  by 
the  harmonic  theory  of  development ;  that  is,  of  the  unequal  posses- 
sion of  features  which  belong  to  different  periods  in  the  develop- 
mental succession  of  the  highest.  There  is  then  another  beauti- 
ful harmony  which  will  ever  remain,  let  the  development  of  each 
sex  be  extended  as  far  as  it  may. 

(c)  In  Men. — If  we  look  at  the  male  sex,  we  shall  find  various 
exceptional  approximations  to  the  female  in  mental  constitution. 
Further,  there  can  be  little  doubt  that  in  the  Indo-European  race 
maturity  in  some  respects  appears  earlier  in  tropical  than  in 
northern  regions  ;  and  though  subject  to  many  exceptions,  this  is 
sufficiently  general  to  be  looked  upon  as  a  rule.  Accordingly,  we 
find  in  that  race — at  least  in  the  warmer  regions  of  Europe  and 
America — a  larger  proportion  of  certain  qualities  which  are  more 
universal  in  women ;  as  greater  activity  of  the  emotional  nature 
when  compared  with  the  judgment ;  an  impressibility  of  the  nerv- 
ous center,  which,  cmteris  paribus,  appreciates  quickly  the  har- 
monies of  sound,  form,  and  color ;  answers  most  quickly  to  the 
friendly  greeting  or  the  hostile  menace  ;  is  more  careless  of  conse- 
quences in  the  material  expression  of  generosity  or  hatred,  and 
more  indifferent  to  truth  under  the  influence  of  personal  relations. 


ON  THE  HYPOTHESIS  OF  EVOLUTION.       1^3 

The  movements  of  the  body  and  expressions  of  the  countenance 
answer  to  the  temperament.  More  of  grace  and  elegance  in  the 
bearing  marks  the  Greek,  the  Italian,  and  the  Creole,  than  the 
German,  the  Englishman,  or  the  Green  Mountain  man.  More  of 
vivacity  and  fire,  for  better  or  for  worse,  is  displayed  in  the  coun- 
tenance. 

Perhaps  the  more  northern  type  left  all  that  behind  in  its 
youth.  The  rugged,  angular  character  which  appreciates  force 
better  than  harmony,  the  strong  intellect  which  delights  in  fore- 
thought and  calculation,  the  less  impressibility,  reaching  stolidity 
in  the  uneducated,  are  its  well-known  traits.  If  there  be  in  such 
a  character  less  generosity  and  but  little  chivalry,  there  is  persist- 
ency and  unwavering  fidelity,  not  readily  obscured  by  the  light- 
ning of  passion  or  the  surmises  of  an  active  imagination. 

All  these  peculiarities  appear  to  result,  first,  from  different  de- 
grees of  quickness  and  depth  in  appreciating  impressions  from 
without ;  and,  seco7id,  from  differing  degrees  of  attention  to  the 
intelligent  judgment  in  consequent  action.  (I  leave  conscience 
out,  as  not  belonging  to  the  category  of  inherited  qualities.) 

The  above  observations  have  been  confined  to  the  Indo-Euro- 
pean race.  It  may  be  objected  to  the  theory  that  savagery  means 
immaturity  in  the  senses  above  described,  as  dependent  largely  on 
"impressibility,"  while  savages  in  general  display  the  least  '* im- 
pressibility," as  that  word  is  generally  understood.  This  can  not 
be  asserted  of  the  Africans,  who,  so  far  as  we  know  them,  possess 
this  peculiarity  in  a  high  degree.  Moreover,  it  must  be  remem- 
bered that  the  state  of  indifference  which  precedes  that  of  impress- 
ibility in  the  individual  may  characterize  many  savages  ;  while 
their  varied  peculiarities  may  be  largely  accounted  for  by  recol- 
lecting that  many  combinations  of  different  species  of  emotion 
and  kinds  of  intelligence  go  to  make  up  the  complete  result  in 
each  case. 

(d)  Conclusions. — Three  types  of  religion  may  be  selected 
from  the  developmental  conditions  of  man  :  first,  an  absence  of 
sensibility  (early  infancy)  ;  second,  an  emotional  stage  more  pro- 
ductive of  faith  than  of  works  ;  thirdly,  an  intellectual  type,  more 
favorable  to  works  than  faith.  Though  in  regard  to  responsibility 
these  states  may  be  equal,  there  is  absolutely  no  gain  to  laboring 
humanity  from  the  first  type,  and  a  serious  loss  in  actual  results 
from  the  second,  taken  alone,  as  compared  with  the  third. 

These,  then,  are  the  physical  vehicles  of  religion— \i  the  phrase 


164  GENERAL  EVOLUTION. 

may  be  allowed — which  give  character  and  tone  to  the  deeper 
spiritual  life,  as  the  color  of  the  transparent  vessel  is  communi- 
cated to  the  light  which  radiates  from  within. 

But  if  evolution  has  taken  place,  there  is  evidently  a  provision 
for  the  progress  from  the  lower  to  the  higher  states,  either  in  the 
education  of  circumstances  (^^  conflict  ")  or  in  the  power  of  an  in- 
terior spiritual  influence  {''  harmony  "),  or  both. 

p.  Evidence  derived  from  History. 

We  trace  the  development  of  Morality  in — first,  the  family,  or 
social  order  ;  second,  the  civil  order,  or  government. 

Whatever  may  have  been  the  extent  of  moral  ignorance  before 
the  Deluge,  it  does  not  appear  that  the  earth  was  yet  prepared  for 
the  permanent  habitation  of  the  human  race.  All  nations  preserve 
traditions  of  the  drowning  of  the  early  peoples  by  floods,  such  as 
have  occurred  frequently  during  geologic  time.  At  the  close  of 
each  period  of  dry  land,  a  period  of  submergence  has  set  in,  and 
the  depression  of  the  level  of  the  earth,  and  consequent  overflow 
by  the  sea,  has  caused  the  death  and  subsequent  preservation  of 
the  remains  of  the  fauna  and  flora  living  upon  it,  while  the  eleva- 
tion of  the  same  has  produced  that  interruption  in  the  process  of 
deposit  in  the  same  region  which  marks  the  intervals  between  ge- 
ologic periods.  Changes  in  these  respects  do  not  occur  to  any  very 
material  extent  at  the  present  time  in  the  regions  inhabited  by  the 
most  highly  developed  portions  of  the  human  race  ;  and  as  the 
last  which  occurred  seems  to  have  been  expressly  designed  for  the 
preparation  of  the  earth's  surface  for  the  occupation  of  organized 
human  society,  it  may  be  doubted  whether  many  such  changes  are 
to  be  looked  for  in  the  future.  The  last  great  flooding  was  that 
which  stratified  the  drift  materials  of  the  north,  and  carried  the 
finer  portions  far  over  the  south,  determining  the  minor  topogra- 
phy of  the  surface  and  supplying  it  with  soils. 

The  existence  of  floods  which  drowned  many  races  of  men  may 
be  considered  as  established.  The  men  destroyed  by  the  one  re- 
corded by  Moses  are  described  by  him  as  exceedingly  wicked,  so 
that  ^'i\\Q  earth  was  filled  with  violence."  In  his  ej-es  the  Flood 
was  designed  for  their  extermination. 

That  their  condition  was  evil  must  be  fully  believed  if  they 
were  condemned  by  the  executive  of  the  Jewish  law.  This  law,  it 
will  be  remembered,  permitted  polygamy,  slavery,  revenge,  ag- 
gressive war.     The  Jews  were  expected  to  rob  their  neighbors,  the 


ON  THE   HYPOTHESIS   OF  EVOLUTION.  165 

Egyptians,  of  jewels,  and  they  were  allowed  *'  an  eye  for  an  eye 
and  a  tooth  for  a  tooth."  They  were  expected  to  butcher  other 
nations,  with  their  women  and  children,  their  flocks  and  their 
herds.  If  we  look  at  the  lives  of  men  recorded  in  the  Old  Testa- 
ment as  examples  of  distinguished  excellence,  we  find  that  their 
standard,  however  superior  to  that  of  the  people  around  them, 
would  ill  accord  with  the  morality  of  the  present  day.  They  were 
all  polygamists,  slaveholders,  and  warriors.  Abraham  treated  Ha- 
gar  and  Ishmael  with  inhumanity.  Jacob,  with  his  mother's  aid, 
deceived  Isaac,  and  received  thereby  a  blessing  which  extended  to 
the  whole  Jewish  nation.  David,  a  man  whom  Paul  tells  us  the 
Lord  found  to  be  after  his  own  heart,  slew  the  messenger  who 
brought  tidings  of  the  death  of  Saul,  and  committed  other  acts 
which  would  stain  the  reputation  of  a  Christian  beyond  redemp- 
tion. It  is  scarcely  necessary  to  turn  to  other  nations  if  this  be 
true  of  the  chosen  men  of  a  chosen  people.  History,  indeed,  pre- 
sents us  with  no  people  prior  to,  or  contemporary  with,  the  Jews 
who  were  not  morally  their  inferiors.* 

If  we  turn  to  more  modern  periods,  an  examination  of  the  mo- 
rality of  Greece  and  Rome  reveals  a  curious  intermixture  of  lower 
and  higher  moral  conditions.  "While  each  of  these  nations  pro- 
duced excellent  moralists,  the  influence  of  their  teachings  was  not 
sufficient  to  elevate  the  masses  above  what  would  now  be  regarded 
as  a  very  low  standard.  The  popularity  of  those  scenes  of  cruelty, 
the  gladiatorial  shows  and  the  combats  with  wild  beasts,  sufficiently 
attests  this.  The  Roman  virtue  of  patriotism,  while  productive 
of  many  noble  deeds,  is  in  itself  far  from  being  a  disinterested 
one,  but  partakes  rather  of  the  nature  of  partisanship  and  selfish- 
ness. If  the  Greeks  were  superior  to  the  Romans  in  humanity, 
they  were  apparently  their  inferiors  in  the  social  virtues,  and  were 
much  below  the  standard  of  Christian  nations  in  both  resj^ects. 

Ancient  history  points  to  a  state  of  chronic  war,  in  which  tlie 
social  relations  were  in  confusion,  and  the  develoi3ment  of  the 
useful  arts  was  almost  impossible.  Savage  races,  which  continue 
to  this  day  in  a  similar  moral  condition,  are,  we  may  easily  be- 
lieve, most  unhappy.  They  are  generally  divided  into  tribes, 
which  are  mutually  hostile,  or  friendly  only  with  the  view  of  in- 
juring some  other  tribe.     Might  is  their  law,  and  robbery,  rapine. 


*  The  evidence  on  this  point  being  very  imperfect,  judgment  may  be  properly 
suspended.     (Ed.  1886.) 


166  GENERAL  EYOLUTIOK 

and  murder  express  their  mutual  relations.  This  is  the  history  of 
the  lowest  grade  of  barbarism,  and  the  history  of  primeval  man  so 
far  as  it  has  come  down  to  us  in  sacred  and  profane  records.  Man 
as  a  species  first  appears  in  history  as  a  sinful  being.  Then  a  race 
maintaining  a  contest  with  tlie  prevailing  corruption  and  exhibit- 
ing a  higher  moral  idea  is  presented  to  us  in  Jewish  history.  Fi- 
nally, early  Christian  society  exhibits  a  greatly  superior  condition 
of  things.  In  it  polygamy  scarcely  existed,  and  slavery  and  war 
were  condemned.  But  jorogress  did  not  end  here,  for  our  Lord 
said,  *^I  have  yet  many  things  to  say  unto  you,  but  ye  can  not 
bear  them  now.  Howbeit,  when  he,  the  sj)irit  of  truth,  is  come, 
he  will  guide  you  into  all  truth." 

The  progress  revealed  to  us  by  history  is  truly  great,  and  if  a 
similar  difference  existed  between  the  first  of  the  human  sj^ecies 
and  the  first  of  whose  condition  we  have  information,  we  can  con- 
ceive how  low  the  oi'igin  must  have  been.  History  begins  with  a 
considerable  progress  in  civilization,  and  from  this  we  must  infer 
a  long  preceding  period  of  human  existence,  such  as  a  gradual 
evolution  would  require. 

y.  Rationale  of  Moral  Development, 

I.  Of  the  Species. — Let  us  now  look  at  the  moral  condition  of 
the  infant  man  of  the  present  time.  We  know  his  small  account- 
ability, his  trust,  his  innocence.  We  know  that  he  is  free  from 
the  law  that  when  he  *^  would  do  good,  evil  is  present  with  him," 
for  good  and  evil  are  alike  unknown.  We  know  that  until  growth 
has  progressed  to  a  certain  degree  he  fully  deserves  the  praise  pro- 
nounced by  our  Saviour,  that  "of  such  is  the  kingdom  of  heaven." 
Growth,  however,  generally  sees  a  change.  We  know  that  the 
buddings  of  evil  appear  but  too  soon  ;  the  lapse  of  a  few  months 
sees  exhibitions  of  anger,  disobedience,  malice,  falsehood,  and 
their  attendants — the  fruit  of  a  corruption  within  not  manifested 
before. 

In  early  youth  it  may  be  said  that  moral  susceptibility  is  often 
in  inverse  ratio  to  physical  vigor.  But  with  growth  the  more 
physically  vigorous  are  often  sooner  taught  the  lessons  of  life,  for 
their  energy  brings  them  into  earlier  conflict  with  the  antagonisms 
and  contradictions  of  the  world.  Here  is  a  beautiful  example  of 
the  benevolent  principle  of  compensation. 

1.  Innocence  and  the  Fall. — If  physical  evolution  be  a  reality, 
we  have  reason  to  believe  that  the  infantile  stage  of  human  mor- 


ON  THE   HYPOTHESIS   OF  EVOLUTION.  157 

als,  as  well  as  of  human  intellect,  was  much  prolonged  in  the  his- 
tory of  our  first  parents.  This  constitutes  the  period  of  human 
purity,  when  we  are  told  by  Moses  that  the  first  pair  dwelt  in 
Eden.  But  the  growth  to  maturity  saw  the  development  of  all 
the  qualities  inherited  from  the  irresponsible  denizen  of  the  forest. 
Man  inherits  from  his  predecessors  in  the  creation  the  buddino-s  of 
reason — he  inherits  passions,  propensities,  and  appetites.  His  cor- 
ruption is  that  of  his  animal  progenitors,  and  his  sin  is  the  low 
and  bestial  instinct  of  the  brute  creation.  Thus  only  is  the  origin 
of  sin  made  clear — a  problem  which  the  pride  of  man  would  have 
explained  in  any  other  way  had  it  been  possible. 

But  how  startling  the  exhibition  of  evil  by  this  new  being  as 
compared  with  the  scenes  of  the  countless  ages  already  past  !  Then 
the  right  of  the  strongest  was  God's  law,  and  rapine  and  destruc- 
tion were  the  history  of  life.  But  into  man  had  been  ^''breathed 
the  breath  of  life,"  and  he  had  "■  become  a  Jiving  soul."  The  law 
of  right,  the  Divine  Spirit,  was  planted  within  him,  and  the  laws 
of  the  beast  were  in  antagonism  to  that  law.  The  natural  devel- 
opment of  his  inherited  qualities  necessarily  brought  him  into  col- 
lision with  that  higher  standard  planted  within  him,  and  that  war 
was  commenced  which  shall  never  cease  "till  he  hath  put  all 
things  under  his  feet."  The  first  act  of  man's  disobedience  con- 
stituted the  Fall,  and  with  it  would  come  the  first  intellectual 
"knowledge  of  good  and  of  evil" — an  apprehension  up  to  that 
time  derived  exclusively  from  the  divinity  within,  or  conscience.* 

2.  Free  Agency. — Heretofore  development  had  been  that  of 
physical  types,  but  the  Lord  had  rested  on  the  seventh  day,  for 
man  closed  the  line  of  the  physical  creation.  Now  a  new  develop- 
ment was  to  begin — the  development  of  mind,  of  morality,  and  of 
grace. 

On  the  previous  days  of  Creation  all  had  progressed  in  accord- 
ance with  inevitable  law  apart  from  its  objects.     Now,  two  lines 

*  In  our  present  translation  of  Genesis,  the  Fall  is  ascribed  to  the  influence  of 
Satan  assuming  the  form  of  the  serpent,  and  this  animal  was  cursed  in  consequence, 
and  compelled  to  assume  a  prone  position.  This  rendering  may  well  be  revised, 
since  serpents,  prone  like  others,  existed  in  both  America  and  Europe  during  the 
Eocene  epoch,  five  times  as  great  a  period  before  Adam  as  has  elapsed  since  his  day. 
Clark  states,  with  great  probability,  that  "serpent"  should  be  translated  monkey  or 
ape — a  conclusion,  it  will  be  observed,  exactly  comciding  with  our  inductions  on  the 
basis  of  evolution.  The  instigation  to  evil  by  an  ape  merely  states  inheritance  in 
another  form.  His  curse,  then,  refers  to  the  retention  of  the  horizontal  position  re- 
tained by  all  other  quadrumana,  as  we  find  it  at  the  present  day. 


168  GENERAL  EVOLUTION. 

of  development  were  at  the  disposal  of  this  being,  between  which 
his  free  will  was  to  choose.  Did  he  choose  the  courses  dictated 
by  the  spirit  of  the  brute,  he  was  to  be  subject  to  the  old  law  of 
the  brute  creation — the  right  of  the  strongest  and  spiritual  death. 
Did  he  choose  the  guidance  of  the  Divine  Guest  in  his  heart,  he 
became  subject  to  the  laws  which  are  to  guide — 1,  tlie  human  spe- 
cies to  an  ultimate  ]3erfection,  so  far  as  consistent  with  this  world  ; 
and,  3,  the  individual  man  to  a  higher  life,  where  a  new  existence 
awaits  him  as  a  spiritual  being,  freed  from  the  laws  of  terrestrial 
matter. 

The  charge  brought  against  the  theory  of  development,  that 
it  implies  a  necessary  progress  of  man  to  all  perfection  without  his 
co-operation — or  necessitarianism,  as  it  is  called — is  unfounded. 

The  free  will  of  man  remains 'the  source  alike  of  his  j^i'ogress 
and  his  relapse.  But  the  choice  once  made,  the  laws  of  spiritual 
development  are  apparently  as  inevitable  as  those  of  matter.  Thus 
men  whose  religious  capacities  are  increased  by  attention  to  the 
Divine  Monitor  within  are  in  the  advance  of  progress — progress 
coinciding  with  that  which  in  material  things  is  called  the  har- 
monic. On  the  other  hand,  those  whose  motives  are  of  the  lower 
origin  fall  under  the  working  of  the  law  of  conjlict. 

The  lesson  derivable  from  the  preceding  considerations  would 
seem  to  be  *^  necessitarian  "  as  respects  the  whole  human  race,  con- 
sidered by  itself ;  and.  I  believe  it  is  to  be  truly  so  interpreted. 
That  is,  the  Creator  of 'all  things  has  set  agencies  at  work  which 
will  slowly  develop  a  perfect  humanity  out  of  his  lower  creation, 
and  nothing  can  thwart  the  jDrocess  or  alter  the  result.  ''  My  word 
shall  not  return  unto  me  void,  but  it  shall  accomplish  that  which 
I  please,  and  it  shall  prosper  in  the  thing  whereto  I  sent  it.^'  This 
is  our  great  encouragement,  our  noblest  hope — second  only  to  that 
which  looks  to  a  blessed  inheritance  in  anotlier  world.  It  is  this 
thought  that  should  inspire  the  farmer,  who,  as  he  toils,  wonders, 
"  Why  all  this  labor  ?  The  Good  Father  could  have  made  me  like 
the  lilies,  who,  though  they  toil  not,  neither  spin,  are  yet  clothed 
in  glory  ;  and  why  should  I,  a  nobler  being,  be  subject  to  the  dust 
and  the  sweat  of  labor  ?  "  This  thought  should  enlighten  every 
artisan  of  the  thousands  that  people  the  factories  and  guide  their 
whirling  machinery  in  our  modern  cities.  Every  revolution  of  a 
wheel  is  moving  the  car  of  progress,  and  the  timed  stroke  of  the 
crank  and  the  rhythmic  throw  of  the  shuttle  are  but  the  music 
the  spheres  have  sung  since  time  began.     A  new  significance  then 


OiT  THE  HYPOTHESIS   OF  EVOLUTION.  169 

appears  in  the  prayer  of  David  :  '^  Let  the  beauty  of  the  Lord  our 
God  be  upon  us,  and  establish  thou  the  work  of  our  hands  upon 
us  :  the  work  of  our  hands,  0  Lord,  establish  thou  it."  But,  be- 
ware of  the  catastrophe,  for  '*  He  will  sit  as  a  refiner";  ''The 
wheat  shall  be  gathered  into  barns,  but  the  chaff  shall  be  burned 
with  unquenchable  fire."     If  this  be  true,  let  us  look  for — 

3.  The  Extinction  of  Evil. — How  is  necessitarianism  to  be 
reconciled  with  free  will  ?  It  appears  to  me,  thus  :  When  a  being 
whose  safety  depends  on  the  perfection  of  a  system  of  laws  aban- 
dons the  system  by  which  he  lives,  he  becomes  subject  to  that 
lower  grade  of  laws  which  govern  lower  intelligences.  Man,  falling 
from  the  laws  of  right,  comes  under  the  dominion  of  the  laws  of 
brute  force  ;  as  said  our  Saviour,  "  Salt  is  good,  but  if  the  salt 
have  lost  his  savor,  it  is  thenceforth  good  for  nothing  but  to  be 
cast  forth  and  trodden  under  foot  of  men." 

In  estimating  the  practical  results  to  man  of  the  actions 
prompted  by  the  lower  i^ortion  of  our  nature,  it  is  only  necessary 
to  carry  out  to  its  full  development  each  of  those  animal  qualities 
which  may  in  certain  states  of  society  be  restrained  by  the  social 
system.  In  human  history  those  qualities  have  repeatedly  had 
this  development,  and  the  battle  of  progress  is  fought  to  decide 
whether  they  shall  overthrow  the  system  that  restrains  them,  or 
be  overthrown  by  it. 

Entire  obedience  to  the  lower  instincts  of  our  nature  insures 
destruction  to  the  weaker,  and  generally  to  the  stronger  also.  A 
most  marked  case  of  this  kind  is  seen  where  the  developed  vices  of 
civilization  are  introduced  among  a  savage  peo2:)le — as,  for  exam- 
ple, the  Korth  American  Indians.  These  seem  in  consequence  to 
be  hastening  to  extinction. 

But  a  system  or  a  circuit  of  existence  has  been  allotted  to  the 
civil  associations  of  the  animal  species  man,  independently  of  his 
moral  development.  It  may  be  briefly  stated  thus  :  Eaces  begin 
as  poor  offshoots  or  emigrants  from  a  parent  stock.  The  law  of 
labor  develops  their  powers,  and  increases  their  wealth  and  num- 
bers. These  will  be  diminished  by  their  various  vices ;  but,  on 
the  whole,  in  proportion  as  the  intellectual  and  economical  ele- 
ments prevail,  wealth  will  increase  —  that  is,  they  accumulate 
power.  When  this  has  been  accomplished,  and  before  activity 
has  slackened  its  speed,  the  nation  has  reached  the  culminating 
point,  and  then  it  enters  upon  the  period  of  decline.  The  re- 
straints imposed  by  economy  and  active  occupation  being  removed. 


170  GENERAL  EVOLUTION. 

the  beastly  traits  find  in  accumulated  power  only  increased  means 
of  gratification,  and  industry  and  prosperity  sink  together.  Power 
is  squandered,  little  is  accumulated,  and  the  nation  goes  down  to 
its  extinction  amid  scenes  of  internal  strife  and  vice.  Its  cycle  is 
soon  fulfilled,  and  other  nations,  fresh  from  scenes  of  labor,  as- 
sault it,  absorb  its  fragments,  and  it  dies.  This  has  been  the 
world's  history,  and  it  remains  to  be  seen  whether  the  virtues  of 
the  nations  now  existing  will  be  suflQcient  to  save  them  from  a 
like  fate. 

Thus  the  history  of  the  animal  man  in  nations  is  wonderfully 
like  that  of  the  type  or  families  of  the  animal  and  vegetable  king- 
doms during  geologic  ages.  They  rise,  they  increase,  and  reach  a 
period  of  multiplication  and  power.  The  force  allotted  to  them 
becoming  exhausted,  they  diminish  and  sink  and  die. 

II.  Of  the  Individual. — In  discussing  physical  development, 
we  are  as  yet  compelled  to  restrict  ourselves  to  the  evidence  of  its 
existence  and  some  laws  observed  in  the  operation  of  its  causative 
force.  What  that  force  is,  or  what  are  its  primary  laws,  we  know- 
not. 

So,  in  the  progress  of  moral  development,  we  endeavor  to  prove 
its  existence  and  the  mode  of  its  operation,  but  why  that  mode 
should  exist,  rather  than  some  other  mode,  we  can  not  explain. 

The  moral  j)rogress  of  the  species  depends,  of  course,  on  the 
moral  progress  of  the  individuals  embraced  in  it.  Eeligion  is  the 
sum  of  those  influences  which  determine  the  motives  of  men's 
actions  into  harmony  with  the  divine  perfection  and  the  divine 
will. 

Obedience  to  these  influences  constitutes  the  practice  of  religion, 
while  the  statement  of  the  growth  and  operation  of  these  influences 
constitutes  the  theory  of  religion,  or  doctrine. 

The  Divine  Spirit  j^lanted  in  man  shows  him  that  which  is  in 
harmony  with  the  Divine  Mind,  and  it  remains  for  his  free  will  to 
conform  to  it  or  reject  it.  This  harmony  is  man's  highest  ideal  of 
happiness,  and  in  seeking  it,  as  well  as  in  desiring  to  flee  from 
dissonance  or  pain,  he  but  obeys  the  disposition  common  to  all 
conscious  beings.  If,  however,  he  attemj)ts  to  conform  to  it,  he 
will  find  the  law  of  evil  present,  and  frequently  obtaining  the 
mastery.  If  now  he  be  in  any  degree  observing,  he  will  find  that 
the  laws  of  morality  and  right  are  the  only  ones  by  which  human 
society  exists  in  a  condition  superior  to  that  of  the  lower  animals, 
and  in  which  the  capacities  of  man  for  happiness  can  approach  a 


ON  THE   HYPOTHESIS   OF  EVOLUTION.  171 

state  of  satisfaction.  He  may  be  then  said  to  be  ^'awakened"  to 
the  importance  of  religion.  If  he  carry  on  the  struggle  to  attain 
to  the  high  goal  presented  to  his  spiritual  vision,  he  will  be  deeply 
grieved  and  humbled  at  his  failures  ;  then  he  is  said  to  be  '' con- 
victed." Under  these  circumstances  the  necessity  of  a  deliverance 
becomes  clear,  and  is  willingly  accepted  in  the  only  way  in  which 
it  has  pleased  the  Author  of  all  to  present  it,  which  has  been  epito- 
mized by  Paul  as  "  the  washing  of  regeneration  and  renewal  of  the 
Holy  Spirit  through  Jesus  Christ."  Thus  a  life  of  advanced  and 
ever-advancing  moral  excellence  becomes  possible,  and  the  man 
makes  nearer  approaches  to  the  *' image  of  God." 

Thus  is  opened  a  new  era  in  spiritual  development,  which  we 
are  led  to  believe  leads  to  an  ultimate  condition  in  which  the  na- 
ture inherited  from  our  origin  is  entirely  overcome,  and  an  exist- 
ence of  moral  perfection  entered  on.  Thus,  in  the  book  of  Mark 
the  simile  occurs  :  ^^  First  the  blade,  then  the  ear,  after  that  the 
full  corn  in  the  ear"  ;  and  Solomon  says  that  the  development  of 
righteousness  "shines  more  and  more  unto  the  perfect  day." 

8.   Summary. 

If  it  be  true  that  general  development  in  morality  proceeds  in 
spite  of  the  original  predominance  of  evil  in  the  world,  through 
the  self-destructive  nature  of  the  latter,  it  is  only  necessary  to  ex- 
amine the  reasons  why  the  excellence  of  the  good  may  have  been 
subject  also  to  progress,  and  how  the  remainder  of  the  race  may 
have  been  influenced  thereby. 

The  development  of  morality  is  then  probably  to  be  understood 
in  the  following  sense  :  Since  the  Divine  Spirit,  as  the  prime  force 
in  human  progress,  can  not  in  itself  be  supposed  to  have  been  in 
any  way  under  the  influence  of  natural  laws,  its  capacities  were  no 
doubt  as  eternal  and  unerring  in  the  first  man  as  in  the  last.  But 
the  facts  and  probabilities  discussed  above  point  to  development 
of  religious  sensiUlity,  or  capacity  to  appreciate  moral  good,  or  to 
receive  impressions  from  the  source  of  good. 

The  evidence  of  this  is  supposed  to  be  seen  m— first,  improve- 
ment in  man's  views  of  his  duty  to  his  neighbor  ;  and,  second,  the 
substitution  of  spiritual  for  symbolic  religions  :  in  other  words, 
improvement  in  the  capacity  for  receiving  spiritual  impressions. 

What  the  primary  cause  of  this  supposed  development  of  re- 
ligious sensibility  may  have  been,  is  a  question  we  reverently  leave 
untouched.     Tliat  it  is  intimately  connected  in  some  way  with, 


172  GENERAL  EVOLUTION. 

and  in  part  dejoendent  on,  the  evolution  of  tlie  intelligence,  appears 
very  probable  ;  for  this  evolution  is  seen — 'first,  in  a  better  under- 
standing of  the  consequences  of  action,  and  of  good  and  of  evil  in 
many  things  ;  and,  second,  in  the  production  of  means  for  the 
spread  of  the  special  instrumentalities  of  good.  The  following 
may  be  enumerated  as  such  instrumentalities  : 

1.  Furnishing  literary  means  of  record  and  distribution  of  the 
truths  of  religion,  morality,  and  science. 

2.  Creating  and  increasing  modes  of  transportation  of  teachers 
and  literary  means  of  disseminating  truth. 

3.  Facilitating  the  migration  and  the  spread  of  nations  holding 
the  highest  position  in  the  scale  of  morality. 

4.  The  increase  of  wealth,  which  multiplies  the  extent  of  the 
preceding  means. 

And  now,  let  no  man  attempt  to  set  bounds  to  this  develop- 
ment. Let  no  man  say  even  that  morality  accomplished  is  all  that 
is  required  of  mankind,  since  that  is  not  necessarily  the  evidence 
of  a  spiritual  development.  If  a  man  possess  the  capacity  for  prog- 
ress beyond  the  condition  in  which  he  finds  liimself,  in  refusing  to 
enter  upon  it  he  declines  to  conform  to  the  divine  law.  For 
*'from  those  to  whom  little  is  given,  little  is  required,  but  from 
those  to  whom  much  is  given,  much  shall  be  required." 


V. 

THE  METHOD  OF  CREATION  OF  ORGANIC  FORMS. 

Chapter  I — Ox  the  Law  of  Acceleration  and  Retardation. — !N"ature 
of  law  of  Natural  Selection.  Two  kinds  of  evidence.  Illustration. 
Examples  from  Cervidae,  HelicidaB,  insects  and  men. 

Chapter  II — The  Law  of  Repetitive  Addition. — Segment  and  cell- 
repetition.  Illustration  from  limbs  and  vertebral  column.  A,  On  seg- 
ment addition ;  definitions.  On  repetition  in  bilateral  and  antero-pos- 
terior  symmetry ;  in  structure  of  compound  teeth ;  in  segments  of 
Articulata;  limbs  of  Reptilia ;  brain  of  lain  prey.  B,  On  cell-repetition ; 
simple  segment  a  repetition  of  cells;  simple  diverticulum  the  same. 
The  cell  theory ;  the  nucleated  cell.  C,  Synthesis  of  repetition.  From 
unicellular  to  multicellular  animals;  simple  repetition  to  compound 
repetition ;  Actinia,  Lepidosiren,  Ichthyosaurus,  Plesiosaurus,  Toenia  ; 
the  heart;  mammalian  teeth.  D,  On  growth-force;  relation  to  other 
forces;  definition.  E,  Direction  of  repetition,  its  location,  centrifugal 
and  longitudinal ;  movements  longitudinal.  Inheritance ;  its  relation 
to  growth-force. 

Chapter  III — The  Law  of  Use  and  Effort. — Points  to  be  investigated. 
A,  On  the  location  of  growth-force.  Relation  of  efi'ort  to  use.  Rudi- 
mental  characters.  Examples  of  growth  under  influence  of  physical 
laws ;  Examples  of  colors  under  influence  of  light.  Use  and  disuse  of 
gills.  Rattlesnake ;  horned  animals.  Teeth  of  ruminants.  B,  Change 
in  amount  of  growth-force.  Local  increase  of  growth-force.  Convo- 
luted structures;  brain,  teeth,  cotyledons.  Absolute  loss  of  growth- 
force.     Teeth  and  toes  of  Ruminants ;  incisors  of  Rodents. 

Chapter  IY — On  Grade  Influence. — A,  On  the  nature  of  Grade  In- 
fluence or  Bathmism.  Definitions.  In  plants;  in  animals.  Increase 
in  time  of  Bathmism  and  growth-force.  Vital  forces  and  vital  in- 
fluences. Thought-force.  Origin  of  Bathmism  in  time.  B,  Physio- 
logical origin  of  Bathmism.  Function  of  nervous  system  in  force- 
conversion.     Automatic  and  habitual   movements.     Eflfect  on  nervous 

system. 
Chapter  V — Intelligent  Selection.— Development  of  intelligence.    Stim- 
uli to  use.     Compulsion,  Choice ;  Bees,  Food,  Rattlesnake ;  Change  of 
color;  Mimetic  analogy  ;  Examples.     Development  of  character. 

In  the  present  state  of  biological  science,  essays  like  the  pres- 
ent can  only  be  tentative  in  so  far  as  they  treat  of  the  laws  of  evo- 


174  GENERAL  EVOLUTION". 

lution.  Nevertheless  the  present  time  is  pre-eminently  one  of 
generalization  in  this  field,  and  properly  so.  Facts  have  been  ac- 
cumulating for  a  long  period,  and  are  now  sufficiently  numerous 
to  yield  important  results,  under  proper  classification  and  induc- 
tion. Darwin  led  the  way  in  this  work,  and  the  development 
hypothesis  is  regarded  as  demonstrated  by  most  biologists.  The 
discussion  of  the  laws  of  its  progress  involves  a  multitude  of 
subordinate  hypotheses.  In  the  following  essay,  these  are  ar- 
ranged under  five  prominent  heads,  viz. :  1.  The  law  of  Accelera- 
tion and  Eetardation;  2.  The  law  of  Repetitive  Addition;  3.  The 
law  of  Use  and  Effort;  4.  The  law  of  Grade  Influence;  5.  The 
law  of  Intelligent  Selection.  Of  these,  the  first  and  second  are 
regarded  by  the  author  as  demonstrated,  the  third  and  fourth  as 
only  reduced  to  a  partial  demonstration,  while  the  fifth  is  a  con- 
sequence of  the  third,  and  stands  or  falls  with  it. 

The  discussion  of  this  subject  divides  itself  into  two  parts, 
viz. :  a  consideration  of  the  proof  that  evolution  of  organic  types 
or  descent  with  modification  has  taken  place  ;  and,  secondly,  the 
investigation  of  the  laws  in  accordance  with  which  this  develop- 
ment has  progressed.  As  the  latter  involves  the  use  of  the  evi- 
dence included  in  the  former,  I  will  not  devote  a  special  chapter 
to  the  proof  for  evolution. 

The  influences  and  forces  which  have  operated  to  produce  the 
type  structures  of  the  animal  kingdom  have  been  plainly  of  two 
kinds  :  1.  Originative ;  2.  Directive.  The  prime  importance  of 
the  former  is  obvious  ;  that  the  latter  is  only  secondary  in  the 
order  of  time  or  succession  is  evident  from  the  fact  that  it  con- 
trols the  preservation  or  destruction  of  the  results  or  creations  of 
the  first,  and  thus  furnishes  the  bases  of  the  exhibitions  of  the 
originative  forces  in  the  production  of  the  successive  generations 
of  living  beings. 

Wallace  and  Darwin  have  propounded  as  the  cause  of  modifi- 
cation in  descent  their  law  of  natural  selection.  This  law  has 
been  epitomized  by  Spencer  as  the  ''survival  of  the  fittest." 
This  neat  expression  no  doubt  covers  the  case,  but  it  leaves  the 
origin  of  the  fittest  entirely  untouched.  Darwin  assumes  a 
''tendency  to  variation"  in  nature,  and  it  is  plainly  necessary  to 
do  this,  in  order  that  materials  for  the  exercise  of  a  selection 
should  exist.  Darwin  and  Wallace's  law  is,  then,  only  restrictive, 
directive,  conservative,  or  destructive  of  something  already  created. 
I  propose  then  to  seek  for  the  originative  laws  by  which  these  sub- 


THE  METHOD  OF  CREATION  OF  ORGANIC  FORMS.  175 

jects  are  furnished — in  other  words,  for  the  causes  of  the  origin  of 
the  fittest. 

It  has  seemed  to  the  author  so  clear  from  the  first  as  to  re- 
quire no  demonstration,  that  natural  selection  includes  no  ac- 
tively progressive  principle  whatever ;  that  it  must  first  wait  for 
the  development  of  variation,  and  then,  after  securing  the  survival 
of  the  best,  wait  again  for  the  best  to  project  its  owm  variations 
for  selection.  In  the  question  as  to  whether  the  latter  are  any 
better  or  worse  than  the  characters  of  the  parent,  natural  selec- 
tion m  no  wise  concerns  itself. 

I.    ON  THE   LAW   OF   ACCELEKATION"   A:N"D   RETAEDATIO]!^-. 

There  are  two  modes  of  demonstration  of  evolution,  both  de- 
pending on  direct  observation.  One  of  these  has  been  success- 
fully presented  by  Darwin.  He  has  observed  the  origin  of 
varieties  in  animals  and  plants,  either  in  the  domesticated  or 
wild  states,  and  has  shown,  what  had  been  known  to  many,  the 
lack  of  distinction  in  the  grades  of  difference  which  separate 
varieties  and  species.  But  he  has  also  pointed  out  that  species 
(such,  so  far,  as  distinctness  goes)  have  been  derived  from  other 
species  among  domesticated  animals,  and  he  infers  by  induction 
that  other  species,  wiiose  origin  has  not  been  observed,  have  also 
descended  from  common  parents.  So  far  I  believe  his  induction 
to  be  justified  ;  but  when  from  this  basis  evolution  of  divisions 
defined  by  important  structural  characters,  as  genera,  orders, 
classes,  etc.,  is  inferred,  I  believe  that  we  do  not  know  enough  of 
the  uniformity  of  Nature's  processes  in  the  premises  to  enable  us 
to  regard  this  kind  of  proof  as  conclusive. 

I  therefore  appeal  to  another  mode  of  proving  it,  and  one 
which  covers  the  case  of  all  the  more  really  structural  features  of 
animals  and  plants. 

It  is  well  known  that  in  both  kingdoms,  in  a  general  way, 
the  young  stages  of  the  more  perfect  types  are  represented  or  imi- 
tated with  more  or  less  exactitude  by  the  adults  of  inferior  ones. 
But  a  true  identity  of  these  adults  with  the  various  stages  of  the 
higher  has,  comparatively,  rarely  been  observed.  Let  such  a  case 
be  supposed. 

In  A  we  have  four  species  whose  growth  attains  a  given 
point,  a  certain  number  of  stages  having  been  passed  prior  to  its 
termination  or  maturity.  In  B  we  have  another  series  of  four 
(the  number  a  matter  of  no  importance),  which,  during  the  period 


176  GENERAL  EVOLUTION". 

of  growth,  can  not  be  distinguished  by  any  common,  i.  e.,  generic 
character,  from  the  individuals  of  group  A,  but  whose  growth 
has  only  attained  to  a  point  short  of  that  reached  by  those  of 
group  A  at  maturity.  Here  we  have  a  parallelism,  but  no  true 
evidence  of  descent.  But  if  we  now  find  a  set  of  individuals  be- 
longing to  one  species,  or,  still  better,  the  individuals  of  a  single 
brood,  and  therefore  held  to  have  had  a  common  origin  or  parent- 
age, which  present  differences  among  themselves  of  the  character 

in  question,   we   have   gained   a  point. 

-~  A  We  know  in  this  case  that  the  individ- 
uals, a,  have  attained  to  the  complete- 
ness of  character  presented  by  group  A, 
while  others,  b,  of  the  same  parentage 
have  only  attained  to  the  structure  of 
those  of  group  B.  It  is  perfectly  obvious 
that  the  individuals  of  the  first  part  of 
the  family  have  grown  further,  and,  therefore,  in  one  sense  faster, 
than  those  of  group  b.  If  the  parents  were  like  the  individuals 
of  the  more  completely  grown,  then  the  offspring  which  did  not 
attain  that  completeness  may  be  said  to  have  been  retarded  in 
their  development.  If,  on  the  other  hand,  the  parents  were  like 
those  less  fully  grown,  then  the  offspring  which  have  added  some- 
thing have  been  accelerated  in  their  development. 

I  claim  that  a  consideration  of  the  uniformity  of  Nature's 
processes,  or  inductive  reasoning,  requires  me  (however  it  may 
affect  the  minds  of  others)  to  believe  that  the  groups  of  species, 
whose  individuals  I  have  never  found  to  vary,  but  which  differ  in 
the  same  point  as  those  in  which  I  have  observed  the  above  varia- 
tions, are  also  derived  from  common  parents,  and  the  more  ad- 
vanced have  been  accelerated  or  the  less  advanced  retarded,  as  the 
case  may  have  been  with  regard  to  the  parents. 

This  is  not  an  imaginary  case,  but  a  true  representation  of 
many  which  have  come  under  observation.  The  developmental 
resemblances  mentioned  are  universal  in  the  animal,  and  probably 
in  the  vegetable  kingdoms,  approaching  the  exactitude  above  de- 
picted in  proportion  to  the  near  structural  similarity  of  the  spe- 
cies considered. 

Example  1. — It  is  well  known  that  the  Cervidm  of  the  Old 
World  develop  a  basal  snag  of  the  antler  (see  Cuvier,  ''  Ossemens 
Fossiles,"  and  Gray,  "  Oat.  British  Museum  ")  at  the  third  year  ;  a 
majority  of  those  of  the  New  World  (genera  Subulo,  Cariacus) 


THE  METHOD  OF  CREATION  OF  ORGANIC  FORMS.  I77 


never  develop  it  except  in  abnormal  cases  in  the  most  vio-orous 
maturity  of  the  most  northern  Cariacus  [C.  viryinianus),  while 
the  South  American  Subulo  retains  to  adult  age  the  simple  horn 
or  spike  of  the  second  year  of  all  Cervidce» 

Among  the  higher  Gervidce^  Eusa  and  Axis  never  assume  char- 
acters beyond  an  equivalent  of  the  fourth  year  of  Cervus.  In 
Dama  the  characters  are,  on  the  other  hand,  assumed  more  rapidly 
than  in  Cervus,  its  third  year  corresponding  to  the  fourth  of  the 
latter,  and  the  development  in  after  years  of  a  broad  plate  of  bone, 
with  points  being  substituted  for  the  addition  of  the  correspond- 
ing snags,  thus  commencing  another  series  which  terminates  in 
the  great  fossil  elk,  Megacerus. 

Returning  to  the  American  deer,  we  have  Blastocerus,  whose 
antlers  are  identical  with  the  fourth  year  of  Cariacus.  Corre- 
sponding with  the  Dama-Megacerus  type  of  the  Old  TVorld,  we 
have  the  moose  (Alces)  developing  the  same  palmate  horn- on  the 
basis  of  Cariacus  (i.  e.,  without  eye-snag). 

Example  2. — I  select  the  following  series,  embracing  the  ma- 
jority of  the  genera  of  the  Korth  American  Helicidse.* 

1.  Turns  of  spire  very  few ;  wide  umbilicus ;  shell  thin,  with  thin  W^s. .  Binneya. 

2.  Turns  few,  but  more  ;  rest  as  above Vitrina. 

3.  Turns  still  more  numerous  ;  rest  as  above Hyalina. 

4.  As  No.  3,  but  lip  thickened  inside Hygromia. 

5.  Coiled  ;  umbilicus  closed ;  lip  thickened  inside  and  out. .  Tachea  and  Pomatia. 

6.  Same,  with  a  parietal  tootl^ Mesodon. 

7.  Same,  with  parietal  and  two  interior  lip  teeth Isognomostoma. 

*    *     Recommencing  at  Xo.  4.     A.\\  ^iih.  open  umbilicus. 

5.  As  No.  4,  but  lip  thickened  in  and  out Arionta. 

6.  Same  as  No.  5,  but  with  parietal  tooth Polymita . 

T.  Same,  with  both  parietal  and  lip  teeth Triodopsis. 

The  successional  relation  of  these  genera  may  be  represented 
in  such  a  diagram  as  this  : 

Umbilicus  open.  Umbilicus  closed. 

Y  *  * 

6  *  * 

5  *  * 

4  * 

3  * 

2  * 

1  * 


*  See  Tryon,  *'  Terrestrial  Mollusca  of  the  United  States."    Probably  other  (e.  g., 
dental)  characters  distinguish  some  of  these  genera,  but  the  above  furnishes  the 
history  of  one  set  of  characters. 
12 


178  GENERAL  EYOLUTIOK 

111  the  history  of  the  growth  of  the  genera  Isognomostoma  and 
Triodopsis,  the  extreme  forms  of  the  two  series,  it  is  well  known 
tliat  at  first  the  coils  of  the  shell  are  extremely  few,  as  in  Binneya  ; 
and  that,  like  it,  it  is  very  thin  and  with  a  delicately  thin  edge  ; 
that  the  turns  increase  successively  in  number,  as  in  Vitrina  and 
Hyalina  ;  and  that,  finally,  the  lip  thickens,  as  in  Hygromia.  Then 
the  umbilicus  may  close,  as  in  Tachea,  or  (in  Triodopsis)  remain 
open,  as  in  Arionta.  In  either  case  a  tooth  is  soon  added  on  the 
body-whorl  (Polymita,  Mesodon),  and,  finally,  the  full  maturity 
of  the  shell  is  seen  in  the  added  teeth  of  the  inside  of  the  lip-mar- 
gin. How  many  of  the  stages  of  the  genera  Triodopsis  and  Meso- 
don are  identical  with  the  genera  of  the  series  which  represent 
them,  I  leave  to  more  thorough  conchologists,  but  that  some  now 
exhibit  and  all  have  once  presented  illustrations  of  the  relation  of 
exact  parallelism,  I  can  not  doubt. 

Example  1. — An  abundant  race  of  the  American  deer,  Caria- 
cus  virgiJiianus,  exists  in  the  Adirondack  region  of  New  York,  in 
which  the  development  of  the  antlers  never  progresses  beyond  the 
spike  stage  of  the  second  year.  Therefore,  some  individuals  of 
this  species  belong  to  Cariacus  and  some  to  Subulo.  * 

Example  2. — A  large  part  of  the  individuals  of  the  common 
snail,  Mesodon  alhokibris,  never  develop  the  tooth  of  the  body- 
whorl,  characteristic  of  the  genus  whose  definition  has  to  be  modi- 
fied to  retain  them. 

Example  3. — Many  individuals  of  Triodopsis  tridentata  from 
eastern  North  Carolina  occur  withotit  the  lip-teeth,  characteristic 
of  the  genus  Triodopsis.  Hence  these  specimens,  though  of  com- 
mon origin  with  others  of  the  species,  must  be  referred  to  another 
genus. 

Example  4. — Structural  characters  are  known  in  many,  if  not 
all,  species  which  are  said  to  be  *^  inconstant,"  being  present  or 
absent  indifferently,  thus  being  useless  for  definition.  They  may 
be  rudimental  when  present  or  considerably  developed.  The  pres- 
ence or  absence  of  wings  in  some  species  of  insects  may  be  cited  ; 
also  the  presence  of  generic  characters  in  the  male  sex  of  many 
Coleoptera  and  their  absence  in  the  females.     The  characters  of 

*  Since  the  above  was  written  the  facts  as  stated  have  been  denied.  But  the 
author  has  seen  specimens  of  Cariacus  virgmianus  and  C.  maa'oiis  in  which  the 
horns  had  assumed  the  characters  of  the  genus  Alces,  throwing  these  individuals 
into  that  genus.     See  "American  Naturalist,"  1883-'84.     (Ed.  1886.) 


THE  METHOD   OF   CREATION   OF  ORGANIC   FORMS.     I79 

males,  females,  workers  and  soldiers  in  bees  and  ants  may  be  added. 
All  these  facts  belong  to  the  same  category  as  those  cited  among 
deer  and  mollusks,  and  have  a  similar  explanation. 

Example  5. — It  does  not  seem  to  be  the  law  in  '^retardation  " 
that  parallelisms  exhibited  by  the  series  in  its  rise  to  its  highest 
point  of  development  should  retrace  the  steps  by  which  it  attained 
it,  and  that  *' exact  parallelisms  "  should  be  exhibited  in  a  reversed 
order.  Parallelisms,  it  is  true,  are  exhibited  ;  but  so  far  as  I  have 
observed  always  'Mnexact,"  often  in  a  high  degree.  A  marked 
case  of  retardation  occurs  in  the  dental  development  of  a  number 
of  persons  who  have  come  under  my  observation  in  the  neighbor- 
hood of  Philadelphia.  It  is  not  very  uncommon  to  find  persons 
in  whom  the  third  molars  in  both  jaws  are  incomplete  as  to  number, 
one,  two,  three,  or  all,  being  deficient.  It  is  still  more  common 
for  them  to  be  incompletely  covered  by  the  enamel  layer,  and  to 
become  in  consequence  so  worthless  as  to  require  early  removal.  I 
am  acquainted  with  two  families  in  which  the  absence  of  the  ex- 
terior upper  incisor  on  each  side  is  common.  In  one  of  these  the 
second  and  third  generation  have  inherited  it  from  the  mother's 
side,  and  it  now  characterizes  many  of  the  children.  The  signifi- 
cance of  this  modification  will  be  best  understood  by  examining 
the  dental  structures  of  the  Qiiadrumana  in  general.  Commencing 
with  the  highest  family  and  its  abnormal  dentition,  w^e  have  : 

Incisors.     Canines.     Premolars.     Molars. 

rr     ■   '1         (  Abnormal.  i  i"  f  a — 2 

(  >iiormal.  f  1  t  t 

Simiidce f  \  I  3 

Cebidce ....  f  "i-  3  f 

LemuridcB f  \  I — 3  3 

Mammalia^  Normal |  \  4  I 

In  this  table  we  see  a  decline  in  the  number  of  teeth  of  the 
higher  groups.  Thus,  the  premolars  are  one  less  than  the  normal 
number  in  the  whole  order,  and  they  lose  one  in  each  jaw  in  tlie 
Old  World  apes,  and  man.  The  molars  maintain  the  normal  num- 
ber throughout,  but  the  third  in  both  jaws  is  in  the  SimiidcB 
reduced  by  the  loss  of  a  fifth  or  odd  tubercle,  thus  becoming  four- 
lobed.  In  the  upper  jaw,  this  is  first  lost  in  the  Semnopithecus  ; 
in  the  lower,  in  the  next  highest  genus  Cercopithecus.  In  Homo 
its  appearance  is  "retarded,"  the  interval  between  that  event  and 
the  protrusion  of  the  second  molar— six  to  ten  years— being  rela- 
tively greater  than  in  any  genus  of  Qiiadrumana.     Its  absence  is 


180  GENEPwAL  EVOLUTION 

then  the  result  of  continued  retardation,  not  of  a  new  and  adaptive 
suppression,  and  is  of  direct  systematic  zoological  value. 

In  the  incisors  a  reduction  is  also  plainly  visible,  as  we  pass 
from  the  most  completely  furnished  mammals  to  the  genus  Homo. 
One  from  the  upper  jaw  is  first  lost,  then,  in  the  Cebidce,  one  from 
the  lower  also.  The  number  remains  the  same  through  the  SimiidcB 
and  normal  Hommidce,  but,  in  the  abnormal  cases  cited,  the  process 
of  reduction  is  continued  and  another  incisor  from  each  side  disap- 
pears. That  this  also  is  truly  *^ retardation"  is  evident  from  the 
fact,  that  the  exterior  incisor  is  the  last  developed,  being  delayed 
in  ordinary  growth  a  year  later  than  those  of  the  inner  pair.  The 
same  retardation  is  seen  in  the  quadrumane  Cheiromys  (the  aye- 
aye),  and  the  whole  order  Rodentia.  In  the  latter,  the  rare  pres- 
ence of  the  reduced  second  incisors,  as  in  Lejjus,  shows  a  less  degree 
of  this  modification.  This  retardation  is  also  of  systematic  impor- 
tance, and,  should  either  of  the  characters  described  be  constant  in 
any  of  the  species  of  the  genus  Homo,  would  at  once  entitle  it  to 
new  generic  rank.  The  very  frequent  absence  of  the  posterior 
molars  (wisdom  teeth)  has  been  recently  found  to  characterize  a 
race  in  India.  Should  this  peculiarity  prove  constant,  this  race 
would  with  propriety  be  referred  to  as  a  new  genus  of  Hominidm, 
as  we  have  many  cases  of  very  similar  species  being  referred  to 
different  genera.  It  is  altogether  probable  that  such  will,  at  some 
future  time,  be  the  condition  of  some  race  or  races  of  men.* 

I  am  now  disposed  to  regard  the  above  as  the  method  of  produc- 
tion, not  only  of  generic  but  of  all  other,  including  specific  char- 
acters. It  would  appear  that,  by  excessive  acceleration  or  retarda- 
tion, some  of  the  characters  of  a  series  may  be  skipped;  but  observa- 
tions are  not  conclusive  on  this  point,  since  very  close  examination 
is  necessary  for  the  appreciation  of  very  transitory  embryonic  con- 
ditions. 

II.    OK   THE   LAW    OF   REPETITIVE   ADDITION. 

The  origin  of  new  structures,  which  distinguish  one  generation 
from  those  which  have  preceded  it,  I  have  stated  to  take  place 
under  the  law  of  acceleration.  As  growth  (creation)  of  parts  usu- 
ally ceases  with  maturity,  it  is  entirely  plain  that  the  process  of 
acceleration  is  limited  to  the  period  of  infancy  and  youth  in  all 
animals.     It  is  also  plain  that  the  question  of  growth  is  one  of 

*  The  preceding  section  is  merely  an  abbreviation,  with  new  illustrations,  of  the 
propositions  brought  forward  in  the  writer's  "  Origin  of  Genera,"  1868,  where  a  con- 
siderable extension  of  the  subject  will  be  found. 


THE   METHOD   OF   CREATION   OF   ORGANIC   FORMS.     181 

nutrition,  or  of  the  construction  of  organs  and  tissues  out  of  pro- 
toplasm. 

The  construction  of  the  animal  types  may  be  referred  to  two 
kinds  of  increase— the  addition  of  identical  segments  and  the  addi- 
tion of  identical  cells.  The  first  is  probably  to  be  referred  to  the 
last,  but  the  laws  which  give  rise  to  it  can  not  now  be  explained. 
Certain  it  is  that  segmentation  is  not  only  produced  by  addition  of 
identical  parts,  but  also  by  subdivision  of  a  homogeneous  part.  In 
reducing  the  vertebrate  or  most  complex  animal  to  its  simplest 
expression,  we  find  that  all  its  specialized  parts  are  but  modifica- 
tions of  the  segment,  either  simply  or  as  sub-segments  of  compound 
but  identical  segments.  Gegenbaur  has  pointed  out  that  the  most 
complex  limb  with  hand  or  foot  is  constructed,  first,  of  a  single 
longitudinal  series  of  identical  segments,  from  each  of  which  a 
similar  segment  diverges,  the  whole  forming  parallel  series,  not  only 
in  the  oblique  transverse,  but  generally  in  the  longitudinal  sense. 
Thus,  the  limb  of  the  Lepidosiren  represents  the  simple  type,  that 
of  the  Ichthyosaurus  a  modification.  In  the  latter,  the  first  seg- 
ment only  (femur  or  humerus)  is  specialized,  the  other  pieces  being 
undistinguishable.  In  the  Plesiosaurian  paddle  the  separate  parts 
are  distinguished,  the  ulna  and  radius  well  marked,  the  carj^al 
pieces  hexagonal,  the  phalanges  defined,  etc. 

As  regards  the  whole  skeleton,  the  same  position  may  be  safely 
assumed.  Though  Huxley  may  reject  Owen's  theory  of  the  verte- 
brate character  of  the  segments  of  the  brain-case,  because  they  are 
so  very  different  from  the  segments  in  other  parts  of  the  column, 
the  question  rests  entirely  on  the  definition  of  a  vertebra.  If  a 
vertebra  be  a  segment  of  the  skeleton,  of  course  the  brain-case  is 
composed  of  vertebrae  ;  if  not,  then  the  cranium  may  be  said  to  be 
formed  of  ^'sclerotomes,"  or  some  other  name  mav  be  used.  Cer- 
tain  it  is,  however,  that  the  parts  of  the  segments  of  the  cranium 
may  be  now  more  or  less  completely  parallelized  or  homologized 
with  each  other,  and  that,  as  we  descend  the  scale  of  vertebrated 
animals,  the  resemblance  of  these  segments  to  vertebrae  increases, 
and  the  constituent  segments  of  each  become  more  similar.  In  the 
types,  as  Amphioxus,  etc.,  where  the  greatest  resemblance  is  seen, 
segmentation  of  either  is  incomplete,  for  they  retain  the  original 
non-osseous  basis.  Other  animals  which  present  cavities  or  parts 
of  a  solid  support  are  still  more  easily  reduced  to  a  simple  basis  of 
segments,  arranged  either  longitudinally  (worm)  or  centrifugally 
(star-fish,  etc.). 


182  GENERAL  EVOLUTION. 

DEFINITIONS. 

a.  The  succession  of  construction  of  parts  of  a  complex,  was 
originally  a  succession  of  identical  repetitions ;  and  grade  influ- 
ence merely  determined  the  number  and  location  of  such  repeti- 
tions. 

(i.  Acceleration  signifies  addition  to  the  number  of  those  repeti- 
tions during  the  period  preceding  maturity,  as  compared  with  the 
preceding  generation,  and  retardation  signifies  a  reduction  of  the 
numbers  of  such  repetitions  during  the  same  time. 

y.  The  successive  additions  now  characterizing  the  growth  of  the 
highest  animals  are  not  exact  repetitions  of  segments  at  this  time, 
because  of  influences  brought  to  bear  on  cell-nutrition  during  long 
periods.  The  nature  of  these  influences  is  made  the  subject  of 
another  section. 

In  the  endeavor  to  prove  these  positions,  I  will  produce  evi- 
dence, first,  that  some  simpler  animals  grow  according  to  the  prin- 
ciple of  modified  repetitive  addition,  and  that  traces  of  it  are  to  be 
observed  in  the  most  complex ;  second,  that  every  addition  to 
structure  which  has  resulted  in  the  complexity  of  the  higher  ani- 
mals was  originally  a  repetition  of  a  pre-existent  structure. 

Detailed  explanations  of  the  law  of  repetitive  addition  are  at- 
tempted in  the  following  pages,  under  two  heads — segment-repeti- 
tion, and  cell-repetition. 

A.    On  Segment- Repetition. 

This  is  everywhere  seen  in  the  construction  of  animals  and 
plants.  Double  bilateral  symmetry  may  serve  as  one  example  of 
repetition  in  growth. 

a.  Bilateral  symmetry.  Anatomists  have  little  diSiculty  in  de- 
termining the  bilateral  symmetry  in  most  animals — that  is,  the 
homologies  of  the  parts  on  opposite  sides  of  the  median  line.  It 
might  be  almost  asserted  that  it  was  a  necessity  of  organization  ; 
but,  when  we  observe  the  growth  of  many  plants,  we  are  unde- 
ceived. And  though  bilateral  symmetry  in  the  Ccelenterata  and 
many  Articulata  is  perfect,  yet  in  higher  animals  it  is  more  or  less 
departed  from.  In  the  Vertebrata  the  Amphioxus  is  almost  com- 
pletely bilaterally  symmetrical.  In  the  fishes,  the  digestive  system 
is  the  only  one  which  does  not  conform  to  it ;  while  in  the  birds 
the  reproductive  system  is  atrophied  on  one  side.  In  the  ser- 
pents the  respiratory  and  part  of  the  circulatory  are  similarly 


THE   METHOD   OF   CREATION   OF   ORGANIC  FORMS.     183 

modified  ;   and  in  the  Mammalia  the  digestive   and   circulatory 
systems  have  both  become  unsymmetrical ;  and  the  cranium,  even 
in  the  Cetacea. 

If  evolution  be  true,  the  unsymmetrical  forms  have  descended 
from  the  symmetrical,  and  the  asymmetry  being  thus  not  inherited, 
is  the  result  of  laws  which  have  interfered  with  the  original  tend- 
ency to  bilateral  repetition. 

Many  cases  of  bilaterally  symmetrical  diseases  have  been  enu- 
merated by  physiologists,  and  I  will  select  as  an  example  one  which 
has  come  under  my  observation.  They  were  those  of  two  boys  who 
had  had  that  disease  involving  the  muco-dermal  system  called  vari- 
cella, while  the  crowns  of  the  successional  incisor  teeth  were  still 
inclosed  in  the  mucous  capsules  of  the  alveolar  walls.  The  deposit 
of  phosphate  of  lime  forming  their  surfaces  was  interrupted  by  the 
disease  of  the  tissue,  and  the  result  was  a  surface  pitted,  or  sculpt- 
ured intaglio  fashion.  The  sculpture  of  the  two  incisors  of  the 
right  side  was  precisely  imitated  by  those  of  the  left  in  reversed 
order,  even  in  minute  details,  which  were  numerous,  thus  produc- 
ing a  result  not  displeasing  to  the  eye.  This  has  been  observed  on 
two  distinct  occasions  some  years  apart. 

Another  interesting  example  of  bilaterally  symmetrical  disease 
is  recorded  in  a  paper  on  ^^  A  Case  of  Universal  Hyperostosis,  etc.," 
by  Drs.  Mears,  Keen,  Allen,  and  Pepper.*  They  describe  the  skele- 
ton of  a  boy  of  fourteen  which  displayed  an  extraordinarily  exos- 
tosed  condition,  the  bones  themselves  remaining  in  the  condition 
known  as  osteoporosis.  They  describe  the  uniform  repetition  of 
the  abnormal  growths  of  one  side  on  the  other  in  the  following 
language  (p.  22)  : 

'^  Comparing  the  two  sides  externally,  not  only  is  there  no  dif- 
ference in  the  extent  and  character  of  the  disease,  but  there  is  the 
most  remarkable  symmetry  of  the  corresponding  diseased  bones, 
which  may  be  traced  even  into  details.  The  disease  begins  and 
ends  on  both  sides  at  corresponding  points,  it  changes  in  character 
from  simple  porosity  to  the  growth  of  osteophytes  at  corres])onding 
points  ;  if,  on  one  side,  the  posterior  part  of  the  bone  is  most  dis- 
eased, the  same  is  true  of  the  other  side  ;  if  the  osteophyte  growth 
is  continuous  or  interrupted  on  one  bone  (fibula,  Fig.  18),  it  is  so 
on  the  opposite  one  ;  if  one  is  unusually  diseased  at  a  tendinous  or 
aponeurotic  insertion,  so  is  its  mate  ;  if  a  groove  or  a  variation  in 


*  See  "Proceed.  Amer.  Philos.  Soc,"  1810,  p.  19. 


184  GENERAL  EVOLUTION. 

color  exist  on  the  one  side,  the  same  will  be  found  on  the  other 
side  ;  even  of  single  marked  spiculae  of  bone  the  same  may  be  said, 
so  that  a  description  of  one  side  will  answer  for  both,  minute  dif- 
ferences being  noted  as  they  occnr." 

h.  Anteroposterior  symmetry. 

That  this  is  an  absolute  law  of  creation  will  be  less  readily  ad- 
mitted than  in  the  case  of  double  bilateral  symmetry,  since  the  ex- 
ceptions appear  to  be  so  universal.  Nevertheless,  I  believe  it  to  be 
as  much  a  part  of  the  law  of  repetitive  nutrition  as  the  other. 
The  anteroposterior  homologies  even  of  the  human  skeleton  have 
been  largely  demonstrated,  bitt,  as  usual,  we  must  appeal  to  the 
lower  forms  for  a  clear  view  of  it.  In  the  rudimental  skeletal  axis 
we  find  such  symmetry  almost  perfect  in  the  AmjoMoxus,  but  in  no 
other  vertebrate.  In  limbs  we  have  it  clearly  indicated  in  the 
Eeptilian  order  Ichthyopterygia,  and  in  the  Piscine  order  Dipnoi, 
where  the  anterior  and  posterior  are  scarcely  or  not  at  all  distin- 
guishable. In  the  scapular  and  pelvic  arches  we  find  it  also  ap- 
proximated in  the  first-named  orders. 

In  the  nervous  system  it  also  exists  approximately  in  the  Am- 
pMoxus.  It  is  not  seen  in  any  vertebrate,  and  in  but  few  other 
animals,  in  the  digestive  system,  but  it  appears  to  exist  in  some 
lower  Articulata  in  both  the  respiratory  and  circulatory  systems. 

c.  As  illustrations  of  exact  repetition  involving  large  portions 
of  the  organism  the  higher  Polyps  may  be  cited,  which  differ  from 
the  lower  chiefly  by  the  addition  of  similar  septa  and  similar  ten- 
tacles. Examples  of  repetition  of  nearly  the  whole  organism  may 
be  found  in  many  Entozoa,  as  Tmnia,  where  the  cephalic  segment 
only  differs  from  the  others,  the  remainder  or  proglottides  being 
alike.  The  most  entire  repetition  of  structure  is  seen  in  Vibrio, 
where  the  segments  are  all  alike,  there  being  none  representing  a 
head. 

d.  As  an  example  in  special  details  of  structure,  the  pelvic  arch 
of  Ichthyosaurus,  when  first  created,  was  a  repetition  of  the  scapu- 
lar, and  the  hind  limb,  of  the  fore  limb.  The  segments  of  the 
limbs  of  the  Dipnoi  are  mere  repetitions,  the  later  created  of  the 
earlier.  The  special  parts  of  the  pes  and  manus  of  Ichthyosaurus 
are  simply  repetitive  efforts  of  growth-force  joined  with  a  dimin- 
ishing amount.  The  addition  of  a  digit,  often  distinguishing  one 
genus  of  Salamanders  or  Saurians  from  another,  is  evidence  of  a 
similar  repetitive  effort.  The  low  mammal  Ornithorhynchus  pos- 
sesses but  a  single  tooth  in  each  jaw  ;  the  simple  teeth  of  armadil- 


THE   METHOD   OF  CEEATION   OF  ORGANTC  FORMS.    185 

los  and  cetaceans,  increasing  as  they  have  done  from  a  simpler 
commencement,  present  examples  of  repetitiye  acceleration  of 
growth-force. 

e.  Complication  of  a  single  element  of  repetition  is  accomplished 
apparently  by  a  double  repetition.  This  is  best  understood  by  the 
consideration  of  the  transition  from  simple  to  complex  teeth.  In 
the  cetaceans  this  occurs  in  the  Squalodonts  ;  the  cylindric  incisors 
are  followed  by  flattened  ones,  then  by  others  grooved  on  the  fang, 
and  then  by  two-rooted,  but  never  double-crowned  teeth.  This  is 
the  result  of  anteroposterior  repetitive  acceleration  of  the  simple 
cylindric  dental  type  of  the  ordinary  toothed  cetacean. 

Another  mode  of  dental  complication  is  by  lateral  repetition. 
Thus,  the  heel  of  the  sectorial  tooth  of  a  Carnivore  is  supported 
by  a  fang  alongside  of  the  usual  posterior  support  of  a  premolar, 
and  is  the  result  of  a  repetitive  effort  of  growth-force  in  a  transverse 
direction.  More  complex  teeth,  as  the  tubercular  molars,  merely 
exhibit  an  additional  lateral  repetition,  and  sometimes  additional 
longitudinal  ones.  As  is  well  known,  the  four  tubercles  of  the 
human  molar  commence  as  similar  separate  knobs  on  the  dental 
papilla. 

The  above  are  cited  as  examples  to  explain  the  meaning  of  the 
proposition.  When  fuller  demonstration  is  desired,  a  greater  num- 
ber might  be  given. 

• 

B.    On  Cell-Repetition. 

That  each  additional  act  of  creation  in  growth  was  originally 
identical  with  one  which  preceded  it,  and  therefore  an  exact  repe- 
tition in  its  character  and  results,  is  proved  by  the  following  con- 
siderations. 

It  has  been  already  determined  by  the  study  of  homologies  that 
all  organs  and  parts  of  an  organism  can  be  referred  to  an  original 
simple  archetype. 

The  question  then  remains  as  to  whether  the  first  element,  or 
lowest  term,  of  a  given  organized  part  is  essentially  a  new  struct- 
ure, or  whether  it  be  a  repetition  of  some  previously  existing  one. 
It  may  be  asserted  that  the  simplest  expressions  which  shall  cover 
all  organs  are  the  solid  segment,  and  the  hollow  sack,  and  tube. 
For  example,  we  have  already  noted  that  the  ultimate  element  of 
the  limb  is  the  first  segment  of  the  single  ray  of  Lepidosiren.  Is 
this  short  cartilaginous  cylinder  (which  probably  represents  the 
fore  limb  of  some  undiscovered  member  of  the  Dipnoi)  a  result  of 


186  GENEKAL  EVOLUTION. 

the  repetition  of  a  pre-existent  structural  element  ?  This  is  no 
doubt  the  case,  for,  as  will  be  shown  beyond,  cartilage,  though  the 
least  cellular  of  all  the  tissues,  is  formed  originally  by  cell  repetition 
or  division.  Again,  the  ultimate  lobules  of  the  most  complex  gland 
are  but  repetitions  of  the  diverticula  of  the  simply  branched,  and 
each  of  the  latter  repetitions  of  the  simple  cul-de-sac,  which  has 
its  origin  in  a  convexity  of  an  originally  plane  surface.  This  con- 
vexity is  again  the  result  of  repetition  of  cells  or  cell-division, 
whereby  their  number  is  increased  and  the  surface  rendered 
convex. 

We  are  thus,  in  both  the  solid  segment  and  hollow  sack,  brought 
down  to  cell-repetition.  Thus  it  is  with  organs,  as  with  entire 
animals,  in  which,  following  the  line  of  simplification,  we  reach  at 
last  forms  composed  of  cells  only  {Act'mojjhrys,  e.  g.)  and  then 
the  unicellular  (Amceba). 

It  this  be  the  origin  of  organs,  the  question  whether  repetitive 
growth  has  constructed  tissues  remains  for  consideration. 

In  growth,  each  segment — and  this  term  includes  the  parts  of 
a  complex  whole  or  parts  always  undivided  (as  the  jaw  of  a  whale 
or  the  sac-body  of  a  mollusk) — is  constructed,  as  is  well  known,  by 
cell-division.  In  the  growing  foetus  the  first  cell  divides  its  nucleus 
and  then  its  whole  outline,  and  this  process,  repeated  millions  of 
times,  produces,  according  to  the  cell  theory,  all  the  tissues  of  the 
animal  organism  or  their  bases,  from  first  to  last.  That  the  ulti- 
mate or  histological  elements  of  all  organs  are  produced  originally 
by  repetitive  growth  of  simj^le  nucleated  cells,  with  various  modifi- 
cations of  exactitude  of  repetition  in  the  more  complex,  is  taught 
by  the  cell  theory.  The  formation  of  some  of  the  tissues  is  as  fol- 
lows : 

First  Change. — Formation  of  simple  nucleated  cells  from  ho- 
mogeneous i^rotoplasm  or  the  cytoblastema. 

Second. — Formation  of  new  cells  by  division  of  nucleus  and  body 
of  the  old. 

Third. — Formation  of  tissues  by  multiplication  of  cells  with  or 
without  addition  of  intercellular  cytoblastema. 

A.  In  connective  tissue,  by  slight  alteration  of  cells  and  addi- 
tion of  cytoblastema. 

B.  In  blood,  by  addition  of  fluid  cytoblastema  (fibrin)  to  free 
cells  (lymph-corpuscles),  which  in  higher  animals  (vertebrates)  de- 
velop into  blood-corpuscles  by  loss  of  membrane,  and  by  cell-devel- 
opment of  nucleus. 


THE   METHOD   OF   CREATION   OF  ORGANIC  FORMS.     187 

C.  In  muscles,  by  simple  confluence  of  cells  end  to  end,  and 
mingling  of  contents  (Kolliker). 

D.  Of  cartilage,  by  formation  of  cells  in  cytoblast  which  break 
up,  their  contents  being  added  to  cytoblast ;  this  occurring  seyeral 
times,  the  result  being  an  extensive  cytoblast  with  few  and  small 
cells  (Vogt).  The  process  is  here  an  attempt  at  development  with 
only  partial  success,  the  result  being  a  tissue  of  small  vitality. 

Even  in  repair-nutrition,  recourse  is  had  to  the  nucleated  cell. 
For  Cohnhcim  first  showed  that  if  the  cornea  of  a  frog's  eye  be 
scarified,  repair  is  immediately  set  on  foot  by  the  transportation 
thither  of  white  or  lymph  or  nucleated  corj^uscles  from  the  neigh- 
boring lymph-heart.  This  he  ascertained  by  introducing  aniline 
dye  into  the  latter.  Repeated  experiments  have  shown  that  this 
is  the  history  in  great  part  of  the  construction  of  new  tissues  in 
the  adult  man. 

Now,  it  is  well  known  that  the  circulating  fluid  of  the  foetus 
contains  for  a  period  only  these  nucleated  cells  as  corpuscles,  and 
that  the  lower  vertebrates  have  a  greater  proportion  of  these  corpus- 
cles than  the  higher,  whence  probably  the  greater  facility  for  repair 
or  reconstruction  of  lost  limbs  or  parts  enjoyed  by  them.  The  in- 
vertebrates possess  only  nucleated  blood-corpuscles. 

C.  Synthesis  of  Repetition. 

That  growth-force  is  capable  of  exhibiting  great  complexity  of 
movement  with  increase  in  amount,  will  now  be  shown.  That  this 
quality  of  comiolication  is  one  of  its  distinguishing  features  will 
appear  plain. 

The  simplest  forms  of  life,  as  stated  by  Haeckel,  are  simply  ho- 
mogeneous drops  of  protoplasm  {Protamoeha).  These  only  grow 
by  ordinary  accretion,  and  display  a  form  of  self  division  or  repro- 
duction which  is  the  simplest  possible — i.  e.,  the  bisection  of  the 
mass  by  contraction  at  opposite  points. 

The  next  grade  of  animal  type  is  represented  by  the  nucleated 
cell.  This  is  simple  in  Amoeha,  complex  in  Actinophrys,  etc. 
With  such  forms  as  the  latter,  cell-growth  begins,  and  its  develop- 
ment is  accomplished,  by  cell-division.  This  is  simple  repetition 
of  ultimate  parts.  In  the  growth  of  all  higher  types  we  have 
nothing  more  than  this,  but  following  a  law  of  complex  repetition. 
Thus  in  the  growth  of  the  parts  of  an  archetypal  vertebral  column 
or  an  archetypal  limb,  we  have  the  repetition  of  cell-growth  till 
the  first  segment  is  formed,  when  it  ceases  at  that  point,  and  re- 


188  GENERAL  EVOLUTION. 

peats  the  process  again,  forming  another  segment  like  the  first ; 
repetition  within  repetition.  So  with  the  construction  of  muscu- 
lar tissue  ;  first,  the  nucleated  cell  repeated  in  a  series,  whose 
adjacent  walls  disappear,  and  whose  cell-contents  flow  together, 
thus  forming  a  fibrilla ;  then  a  repetition  of  the  same  process, 
forming  a  second  fibrilla  ;  and  so  on  to  the  completion  of  thou- 
sands of  them  in  fasciculi. 

Let  us  then  trace  the  series  of  repetitions  and  duplicated  and 
still  more  complex  repetitions,  seen  in  following  up  animal  forms 
from  their  archetypes. 

In  the  simplest  rejDetition  of  cell-growth  in  a  longitudinal 
direction  we  have  Vibrio  ;  in  the  centrifugal,  Actinophrys.  The 
former  may  be  represented  by  a  line  of  simple  dots,  thus  :  Fig.  1. 

A.^... _.. ^ 


S.y"       *V ' 


J   Ci  ao  to  aQOoa      ^.  ooQOococ3cCf  cO  ^3  O 
f"  o  cjqOoc5  ^rs  O        oodODCD£i:n  c:i>  o    ^^O, 

\ 

In  a  complex  repetition  we  rarely  have  the  same  degree  of  com- 
plication in  each  repeated  part.  We  have  it  centrifugally  almost 
perfect  in  a  Coelenterate  {Actinia),  and  linearly  in  some  of  the 
lower  vermes.  An  archetype  of  the  latter  kind  might  be  repre- 
sented thus  :  Fig.  2.  In  a  more  complex  form,  as  of  the  pro- 
glottides of  TcBnia,  thus  :  Fig.  3.  The  same  might  represent  an 
archetypal  vertebrate. 

If  now  we  attempt  to  express  the  complication  of  an  organ  by 
modified  repetition  of  once  identical  parts,  the  history  of  extremi- 
ties will  serve  us.  Thus  the  limb  of  Lepidosiren,  which  is  com- 
posed of  identical  segments,  may  be  thus  represented  :  Fig.  2. 
Each  longitudinal  segment  of  the  limb  of  Ichthyosaurus  may  be 
similarly  represented  with  a  modification,  in  size  only,  of  the 
proximal  or  humerus ;  thus  :  Fig.  4.  But  in  Plesiosatirus  an 
important  series  of  changes  of  shape  (but  not  in  complexity)  ap- 
pears, which  may  be  represented  thus  :  Fig.  5  ;  the  first  being 


THE  METHOD   OF  CREATION   OF  ORGANIC  FORMS..    189 

humerus,  second  ulna,  third  and  fourth  carpals  (tarsals),  the  last 
phalanges,  which  are  first  specialized  in  this  genus. 

By  far  the  most  usual  modification  is,  however,  complication  bv 
duplicated  and  triplicated  and  still  more  highly  multiplied  repeti- 
tion in  some  segments  of  the  archetype,  and  its  omission  in  other 
segments.  Thus  in  the  Tcenia,  the  cejihalic  segments  are  much 
modified,  and  the  nature  of  the  repetition  might  be  thus  ex- 
pressed :  Fig.  6  ;  the  simpler  segments  representing  the  body 
segment,  the  two  complex  representing  those  of  the  head.  In 
each,  it  will  be  observed,  the  complication  is  represented  by  loops 
of  similar  form,  and  each  loop  of  dots  which  represent  the  cells  in 
the  first  linear  (Fig.  1)  arrangement. 

A  somewhat  similar  figure  might  represent  the  nature  of  the 
complication  in  the  Myriapod.  In  the  insect  the  additional  com- 
plications of  the  thoracic  segments  would  alter  the  diagram  near 
the  middle. 

In  the  vertebrate  cranium  a  somewhat  similar  diagram  might 
be  used,  except  that  the  modification  of  the  segments  or  vertebrae, 
as  compared  with  the  segments  of  the  vertebral  column,  is  not  by 
rciDctition  with  modification  of  the  parts  of  each  segment,  but 
rather  by  modification  of  the  forms  of  the  parts  of  the  segments. 
The  basicranial  segments  thus  compare  with  the  dorsal  vertebrae 
as  the  segments  of  the  limb  of  Plesiosaurus  do  with  those  of  Ich- 
thyosaurus. 

The  above  considerations  have  reference  to  repetition  of  parts 
in  a  linear  direction.  Centrifugal  repetition  is  seen  in  the  addi- 
tion of  chambers  to  the  heart,  by  the  subdivision  in  the  earliest 
stages  into  auricle  and  ventricle  in  the  linear  direction,  con- 
sidered in  connection  with  the  earlier  division  of  each  in  the 
transverse  direction  by  the  growth  of  partitions.  This  mode  of 
repetitive  addition  is  not  readily  represented  by  diagram. 

A  good  example  of  repetitive  addition,  in  both  linear  and 
transverse  direction,  may  be  found  in  the  successive  complication 
of  tooth  structure  seen  in  Mammalia.  In  the  dolphin,  the  dental 
series  may  be  represented  thus  :  Fig.  7  ;  in  the  squalodon  thus  : 
Fig.  8  ;  in  the  cat :  Fig.  9  ;  in  the  dog  :  Fig.  10  :  in  man  :  Fig. 
11 ;  in  some  Insectivora  :  Fig.  12. 

The  circles  represented  here  are  each  a  simple  cusp. 

In  conclusion,  the  directions  of  repetitive  growth  may  be 
tabulated  as  follows  :  The  types  to  the  left  represent  the  original ; 
to  the  right,  the  derivative  : 


190  GENERAL  EVOLUTION. 


Centrifugal. 


'  More  bilaterally  {  n  ^    ^.'^  ^.      ^ 
symmetrical.    ']  Only  bilateral. 

Longitudinal  antero-pos-  -< 
terior  and  bilateral. 

More  antero-pos-  j  Only  antero- 
teriorly.  (  posterior. 

(  In  plane. 
Centrifugal.  •< 

(  In  globe. 

D.   On  Growtli-Force. 

From  such  examples  as  those  that  precede,  but  more  especially 
from  the  last,  it  seems  necessary  to  believe  that  there  resides  in 
organized  matter,  and  in  its  most  unmodified  representative,  the 
nucleated  cell,  an  affection  which  displays  itself  in  repetition. 
This  phenomenon  reduced  to  its  lowest  terms,  may  mean  cell-divis- 
ion only,  but  the  proof  is  only  clear  in  cases  of  gi'owth  proper. 
This  affection  displays  itself  in  very  slow  or  more  rapid  repetitions 
— cell-division  in  growth  occurring  rapidly,  while  its  recurrences 
at  rutting  seasons  in  the  development  of  horns,  feathers,  etc.,  are 
separated  by  long  intervals  of  time.  In  acceleration  these  repeti- 
tions occur  with  increased  rapidity,  i.  e.,  in  the  adding  of  more 
structures  during  the  same  growth  periods,  while  in  low  types  its 
repetitions  are  few  and  therefore  slow. 

What  is  the  relation  of  cell-division  to  the  forces  of  nature,  and 
to  which  of  them  as  a  cause  is  it  to  be  referred,  if  to  any  ?  The 
animal  organism  transfers  solar  heat  and  the  chemism  of  the  food 
(protoplasm)  to  correlated  amounts  of  heat,  motion,  electricity, 
light  (phosphorescence),  and  nerve  force.  But  cell-division  is  an 
affection  of  protoplasm  distinct  from  any  of  these  ;  although  addi- 
tion to  homogeneous  lumps  or  parts  of  protoplasm  (as  in  that  low- 
est animal,  Protamceha  of  Hseckel)  should  prove  to  be  an  exhibi- 
tion of  mere  molecular  force,  or  attraction,  cell-division  is  certainly 
something  distinct.  It  looks  like  an  exhibition  of  another  force, 
which  may  be  called  groiuth-force.  It  is  correlated  to  the  other 
forces,  for  its  exhibitions  cease  unless  the  protoplasm  exhibiting  it 
be  fed. 

Professor  Henry  i^ointed  out  many  years  ago  that  this  must  be 
the  case,  basing  his  belief  on  the  observed  phenomena  of  growth  in 
the  potato,  and  in  the  Qgg.  The  starch  of  the  potato  weighs  much 
more  than  the  young  shoot  of  cellulose,  etc.,  into  which  it  has  been 
converted  by  growth-activity,  so  that  a  portion  of  the  substance 
of  the  tuber  has  evidently  escaped  in  some  other  direction.     This 


THE  METHOD  OF  CREATION  OF  ORGANIC  FORMS.     191 

is  shown  to  be  carbonic  acid  gas  and  water,  derived  from  the  slow 
combustion  of  the  starch,  which  in  thus  running  down  from  the 
complex  organic  state  to  the  more  simple  inorganic  compounds, 
evolves  an  amount  of  force  precisely  equal  in  amount  to  the  chemi- 
cal force  (or  chemism)  requisite  to  bind  together  the  elements  in 
the  more  complex  substance.* 

Carpenter  also  states  that  in  his  opinion  the  growth  of  the  Funo-i 
is  produced  by  a  force  liberated  by  the  retrograde  metamorpliosts 
of  their  food,  which  is  of  an  organic  character  (i.  e.,  humus). 
This  metamorphosis  consists,  as  in  the  tuber,  in  the  production  of 
carbonic  acid  gas  and  water,  and  a  force  equivalent  to  the  chemism 
which  had  bound  them  in  the  former  complex  union,  f  But  in 
higher  forms  of  vegetable  life,  and  in  growth  that  follows  germina- 
tion, the  plant  must  appropriate  carbon  from  the  carbonic  acid  of 
the  atmosphere.  The  decomposition  of  the  binary  compound 
(which  sets  free  its  oxygen)  liberates  the  chemical  force  which  luid 
previously  maintained  the  compound  (or  an  equivalent  force),  which 
Henry  regards  as  furnishing  the  growth-force,  which  produces  the 
plant.  Carpenter  derives  but  a  portion  of  the  force  in  this  way, 
obtaining  the  greater  part  from  the  heat  of  the  sun.  To  this  source 
also  he  looks  for  the  heat  necessary  to  the  construction  of  cold- 
blooded animals  ;  while  in  warm-blooded  animals,  the  retrograde 
metamorphosis  or  running  down  of  the  material  (protoplasm)  of 
the  food  furnishes  a  requisite  amount  of  heat. 

Growth-force  we  may  then  regard  as  potential  in  organized  tis- 
sue, and  as  energetic  during  growth.  J;     Our  present  knowledge 


*  "Agricultural  Report  of  the  Patent  Office,"  ISSY. 

•(•  "  Correlation  of  Physical  and  Vital  Forces,"  1864  ("  Quarterly  Jour,  of  Science  "). 

j:  Bathmism  or  growth-force  must  be  static  or  potential  in  each  unit  or  plastid 
(cell)  of  a  living  organism,  the  type  differing  with  each  organic  species.  When  it  is 
in  excess  in  a  given  locality  it  becomes  energetic,  and  builds  tissue  in  various  forms. 
A  portion  of  this  energy  is,  in  this  process,  developed  as  molar  motion  of  nutritive 
material,  and  is  accompanied  in  the  completed  structure  by  the  ordinary  cohesive 
energy,  by  which  the  newly-built  material  maintains  its  attachment  as  a  whole  and 
in  its  parts.  If  living  tissue  be  constructed,  a  portion  of  the  excess  remains  as  the 
static  energy  of  the  plastids  or  cells  of  the  new  part,  as  it  did  of  the  old.  The 
spermatozoid  is  highly  endowed  with  static  bathmism,  and  communicates  it  to  the 
female  ovum.  The  mingling  of  the  two  elements  in  the  presence  of  nutritious  ma- 
terial presents  an  excess,  and  form-building  results.  Its  activity  will  regulate  sub- 
sequent new  growth,  by  giving  the  motion  of  nutritive  material  its  proper  direc- 
tion. When  the  tissue  dies,  this  energy  must  leave  behind  a  dynamic  equivalent, 
but  what  this  may  be  is  as  yet  a  mystery.     (Ed.  1886.) 


192  ^         GENERAL  EVOLUTION". 

only  permits  us  to  believe  that  other  force  is  only  conA^erted  into 
it  under  the  influence  of  pre-existent  life,  but  of  the  real  cause  of 
this  conversion  we  are  as  ignorant  as  in  the  case  of  the  physical 
forces. 

In  the  animal  organism,  different  tissues  display  different  de- 
grees of  ^^  vitality."  The  most  vital  display  cell-organization  and 
its  derivative  forms,  while  the  least  so,  approach  nearer  to  homo- 
geneity. As  organized  tissue  is  the  machine  for  converting  vital 
forces,  we  may  believe  that  less  growth-force  is  potential  as  such  in 
cartilage  than  in  muscle,  for  it  is  formed  by  a  retrograde  process, 
by  which  cells  once  formed  are  mostly  lost,  and  the  contents  form 
the  intercellular,  nearly  structureless  mass  characteristic  of  this 
tissue.  Growth-force  must  be  here  liberated  in  some  other  form, 
perhaps  the  mere  cohesive  force  of  the  former  or  ^^ dead"  inter- 
cellular substance. 

The  higher  vitality  we  may  believe  to  result  from  the  greater 
perfection  of  the  more  complex  tnacliine  as  a  force  converter,  as 
compared  with  the  ineiSiciency  of  the  more  simple. 

E,   On  the  Diredioii  of  Repetition, 

It  has  been  already  pointed  out  ihoi  groiutli-force  exhibits  itself 
in  cell  or  segment  re^Dctition.  The  forms  in  which  it  thus  displays 
itself  may  be  briefly  considered.  The  approximate  cause  is  treated 
of  in  the  next  chapter  ;  but  enough  may  be  shown  here  to  indicate 
that  duplication  and  complex  duplication  is  the  law  of  growth-force, 
and  that  therefore  this  process  must  always  follow  an  increase  in 
a7nount  in  any  given  locality. 

The  size  of  a  part  is  then  dependent  on  the  amount  of  cell-divis- 
ion or  growth-force,  which  has  given  it  origin,  and  the  number 
and  shape  of  segments  is  due  to  the  same  cause.  The  whole  ques- 
tion, then,  of  the  creation  of  animal  and  vegetable  types  is  reduced 
to  one  of  the  amount  and  location  of  groiuth-force. 

Repetition  is  of  two  kinds,  centrifugal  and  longitudinal.  As 
an  example  of  the  former,  the  genus  Actinoplirys  has  been  cited, 
where  the  animal  is  composed  of  cells  arranged  equidistally  around 
a  common  center.  The  arrangement  in  this  type  may  be  dis- 
coidal  or  globular,  providing  no  definite  axis  be  discoverable.  As 
an  example  of  longitudi^ial  repetition.  Vibrio,  and  numerous 
cellular  plants  may  be  cited,  where  the  arrangement  is  in  a  single 
line. 

In  by  far  the  greater  number  of  animals  these  kinds  of  repeti- 


THE  METHOD   OF   CREATION   OF  ORGANIC  FORMS.     I93 

tive  structure  co-exist.  The  loyigitudinal  is,  however,  predomi- 
nant in  the  Vertedrata,  Mollusca,  and  Articulata,  while  the  cen- 
trifugal is  greatly  developed  in  the  Ooelenterata  and  Radiata.  In 
none  but  the  simplest  forms  are  either  of  these  modes  to  be  found 
alone. 

The  centrifugal  repetition,  or  addition,  more  nearly  resembles 
the  mode  of  aggregation  of  atoms  in  inorganic  or  crystalline 
bodies,  and  hence  may  be  regarded  as  the  inferior  manifestation. 
It  implies  that  growth-force  in  this  case  conforms  to  a  law  of 
polarity  in  exhibiting  itself  at  equal  distances  from  a  center — 
which  is  allied  to  ordinary  molecular  force,  and  independent  of 
the  localizing  influences  of  which  higher  organisms  seem  capable. 
In  centrifugal  animals,  then,  the  latter  evidently  plays  an  in- 
ferior part.  In  Coelenterates  and  Radiates,  however,  the  body 
possesses  a  short  longitudinal  axis,  in  some  (Asterias)  very  short, 
in  others  (Holothuria)  more  elongate.  The  amount  of  com- 
plication of  centrifugal  growth  greatly  exceeds  the  complication 
in  a  longitudinal  direction  in  all  of  these  animals  except  the 
Holothurida. 

It  is  now  important  to  observe  that  great  numbers  of  centrifu- 
gal animals  are  sedentary  or  sessile  ;  while  the  longitudinal  are 
vagrant,  moving  from  place  to  place.  Many  of  the  centrifugal 
animals  which  wander,  do  not  do  so  in  the  direction  of  their  axis, 
but  sideways  {Medusce).  It  is  also  proper  to  notice  that  not  only 
the  movements  of  the  muscles  but  also  the  direction  taken  by 
the  food  is  in  the  long  axis.  It  is  therefore  to  be  concluded  that 
in  longitudinal  animals  growth-force  has  assumed  a  more  truly 
animal  type,  and  that  this  tendency  has  predominated  over  the 
polar  or  molecular  tendency. 

In  most  longitudinal  animals,  however,  certain  lateral  portions, 
limbs,  etc.,  extend  on  each  side  of  the  axis  ;  and  were  the  space 
marked  by  their  extremities,  and  the  extremities  of  the  axis,  filled, 
we  would  have  the  outline  of  a  centrifugal  animal. 

Before  discussing  the  influences  which  have  increased  and  lo- 
cated growth-force,  it  will  be  necessary  to  point  out  the  mode  in 
which  these  influences  must  necessarily  have  effected  growth. 
Acceleration  is  only  possible  during  the  period  of  growth  in  ani- 
mals, and  during  that  time  most  of  them  are  removed  from  the 
influence  of  physical  or  biological  causes,  either  through  their 
hidden  lives  or  incapacity  for  the  energetic  performance  of  life 
functions.      These  influences  must,  then,  have  operated  on  the 

13 


194  GENERAL  EVOLUTION, 

parents,  and  become  energetic  in  the  growing  foetus  of  the  next 
generation.  However  little  we  may  understand  this  mysterious 
process,  it  is  nevertheless  a  fact.  Says  Murphy,  ''  There  is  no  act 
which  may  not  become  habitual,  and  there  is  no  habit  that  may 
not  be  inherited."  Materialized,  this  maybe  rendered — there  is 
no  act  which  does  not  direct  growth-force,  and  therefore  there  is 
no  determination  of  growth-force  which  may  not  become  habitual ; 
there  is,  then,  no  habitual  determination  of  growth-force  which 
may  not  be  inherited  ;  and,  of  course,  in  a  growing  foetus  becomes 
at  once  energetic  in  the  production  of  new  structure  in  the  direc- 
tion inherited,  which  is  acceleration. 

But  if  the  forces  converted  into  growth-force  are  derived  from 
without  the  animal  organism,  whence  and  what  the  agency  by 
which  the  acceleration  or  retardation  of  the  latter  is  inherited 
from  the  parent  ?  A  few  suggestions  only  on  this  head  can  be 
made  in  the  fourth  section. 

III.    THE   LAW   OF   USE   AKD   EFFORT. 

Up  to  this  point  we  have  followed  paths  more  or  less  distinctly 
traced  in  the  field  of  nature.  The  positions  taken  appear  to  me 
either  to  have  been  demonstrated  or  to  have  a  great  balance  of 
probability  in  their  favor.  In  the  closing  part  of  this  paper  I 
shall  indulge  in  more  of  hypothesis  than  heretofore. 

Since  repetitive  addition  only  produces  identical  results  in 
archetypes,  and  each  effort  produces  results  more  and  more  unlike 
its  predecessor  as  structure  becomes  specialized,  it  becomes  im- 
portant to  examine  into  the  influences  which  have  originally 
modified  the  repetitive  efforts  successively,  producing  structures 
more  or  less  different  in  detail  in  the  second  generation  from 
those  of  the  parents,  in  acceleration,  or  the  reverse,  in  retarda- 
tion. 

Going  further  back,  the  question  arises,  why  a  simple  exhibi- 
tion of  repetition  (e.  g.,  cell-division)  should  be  converted  into  a 
complex  or  duplicated  repetition  (e.  g.,  jointed  ray).  This,  it  has 
already  been  stated,  is  one  consequence  of  increased  amount  of 
the  growth-force. 

We  then  seek  explanation  of  the  main  question,  as  to  what  de- 
termines the  location  of  this  additional  or  new  growth-force. 
(Div.  A.) 

Lastly,  why  the  total  amount  of  this  force  should  change  in  a 
given  individual  or  part  of  an  individual.     (Div.  B.) 


THE  METHOD   OF  CREATION  OF  ORGANIC  FORMS.     I95 

A.   On  the  Location  of  Groivth-Force. 

What  are  the  influences  locating  growth-force  ?  The  only 
efficient  ones  with  which  we  are  acquainted,  are,  first,  physical 
and  chemical  causes  ;  second,  use  ;  and  I  would  add  a  third,  viz.  : 
effort.  I  leave  the  first,  as  not  especiaUy  prominent  in  the  econo- 
my of  type-growth  among  animals,  and  confine  myself  to  the  two 
following.  The  effects  of  use  are  well  known.  We  can  not  use 
a  muscle  without  increasing  its  bulk  ;  we  can  not  long  use  the 
teeth  in  mastication  without  inducing  a  renewed  deposit  of  den- 
tine within  the  pulp-cavity  to  meet  the  encroachments  of  attri- 
tion. The  hands  of  the  laborer  are  always  larger  than  those  of 
men  of  other  pursuits.  Pathology  furnishes  us  with  a  host  of  hy- 
pertrophies, exostoses,  etc.,  produced  by  excessive  use,  or  neces- 
sity for  increased  means  of  performing  excessive  work.  The 
tendency,  then,  induced  by  use  in  the  parent,  is  to  add  segments 
or  cells  to  the  organ  used.  Use  thus  determines  the  locality  of 
new  repetitions  of  parts  already  existing,  and  determines  an  in- 
crease of  growth-force  at  the  same  time,  by  the  increase  of  food 
always  accompanying  increase  of  work  done,  in  every  animal. 

But  supposing  there  be  no  part  or  organ  to  use.  Such  must 
have  been  the  condition  of  every  animal  prior  to  the  appearance 
of  an  additional  digit  or  limb  or  other  useful  element.  It  ap- 
pears to  me  that  the  cause  of  the  determination  of  grow^th -force 
is  not  merely  the  irritation  of  the  part  or  organ  used  by  contact 
with  the  objects  of  its  use.  This  would  seem  to  be  the  remote 
cause  of  the  deposit  of  dentine  in  the  used  tooth  ;  in  the  thicken- 
ing epidermis  of  the  hand  of  the  laborer ;  in  the  wandering  of 
the  lymph-cells  to  the  scarified  cornea  of  the  frog  in  Cohnheim's 
experiment.  You  can  not  rub  the  sclerotica  of  the  eye  without 
producing  an  expansion  of  the  capillary  arteries  and  correspond- 
ing increase  in  the  amount  of  nutritive  fluid.  But  the  case  may 
be  different  in  the  muscles  and  other  organs  (as  the  pigment  cells 
of  reptiles  and  fishes)  which  are  under  the  control  of  the  volition 
of  the  animal.  Here,  and  in  many  other  instances  which  might 
be  cited,  it  can  not  be  asserted  that  the  nutrition  of  use  is  not 
under  the  direct  control  of  the  will  through  the  mediation  of 
nerve  force.  Therefore  I  am  disposed  to  believe  that  growth- 
force  may  be,  through  the  motive,  force  of  the  animal,  as  readily 
determined  to  a  locality  where  an  executive  organ  does  not  exist, 
as  to  the  first  searment  or  cell  of  such  an  organ  already  com- 


196  GENERAL  EVOLUTION. 

menced,  and  that  therefore  effort  is,  in  the  order  of  time,  the 
first  factor  in  acceleration. 

Addition  and  subtraction  of  growth-force,  in  accordance  with 
the  modes  pointed  out  below,  account  for  the  existence  of  many 
characters  which  are  not  adaptive  in  their  nature. 

Acceleration  under  the  influence  of  effort  accounts  for  the  ex- 
istence of  rudiments  of  organs  in  process  of  develoj)ment,  while 
rudiments  of  organs  in  process  of  extinction  are  results  of  retarda- 
tion, occasioned  by  absolute  or  complementary  loss  of  growth-force. 
Many  other  characters  will  follow,  at  a  distance,  the  modification 
resulting  from  the  operation  of  these  laws. 

Examples  of  the  Influence  of  Physical  Causes. — This  is  nowhere 
better  seen  than  in  the  case  of  coloration,  which  requires  the  light 
of  the  sun  for  its  production.  The  most  striking  examples  of  this 
are  seen  in  the  colorless  surface  of  animals  inhabiting  the  recesses 
of  cayes,  as  the  blind  craw-fish  and  the  AmUyopsis,  etc.  If  evolu- 
tion be  true,  these  have  descended  from  more  highly  colored  jDro- 
genitors.  The  flat  fishes,  also  {Pleuronectidce),  as  is  known,  swim 
on  one  side  in  adult  age,  but  many  of  them  are  hatched  symmetrical 
fishes,  or  nearly  so,  one  eye  rotating  from  one  side  to  the  other  by 
a  twisting  of  the  cranial  bones.  It  is  thus  probable  that  they  have 
descended  from  symmetrical  fishes,  which  were  similarly  colored 
on  both  sides.  Now  the  lower  side  is  colorless,  the  upj^er  retain- 
ing often  brilliant  hues.  The  influence  of  sunlight  is  thus  as  dis- 
tinctly discoverable  among  animals  as  among  plants,  where  it  has 
been  generally  accepted  as  a  principle  of  vegetable  physiology.* 

Examples  of  the  Effects  of  Effort  and  Use. — a.  The  Respiratory 
and  Circulatory  System  of  Vei^tehrates.  — It  is  well  known  that  the 
succession  of  classes  of  Vertebrates  is  measured  first  by  their  adapta- 
tion to  aeration  in  water,  and  then  by  their  successive  departures 
from  this  type  in  connection  with  the  faculty  of  breathing  air. 
The  same  succession  of  structure  is  traversed  by  the  embryos  of 
the  vertebrates,  the  number  of  stages  passed  being  measured  by 
the  final  status  of  the  adult.  This  transition  takes  place  in  the 
Batrachia  later  in  development  than  in  any  other  class.  Now,  it 
is  well  known  that  the  transition  or  metamorphosis  may  be  delayed 

*  In  this  and  similar  cases,  care  must  be  taken  not  to  misunderstand  the  writer 
by  supposing  him  to  mean  that  in  each  generation  separately  the  peculiar  coloration 
is  the  result  of  changed  exposure  to  light.  The  evolutionist  will  understand  that  the 
effect  of  such  influence  increases  with  succeeding  generations  by  the  addition  to  in- 
herited character  of  the  effect  of  immediate  external  cause. 


THE  METHOD   OF   CREATION   OF   ORGANIC   FORMS.     197 

or  encouraged  by  suppression  of  use  of  the  branchial  and  encourage- 
ment of  use  of  the  pulmonary  organs,  or  the  reverse. 

The  aquatic  respiration  of  tadpoles  may  be  indefinitely  pro- 
longed by  preventing  their  access  to  the  surface,  and  it  is  known 
that  in  nature  the  size  or  age  of  the  larva  at  time  of  metamorphosis 
may  vary  much  in  the  same  species.  If  perennibranchiates  (Siren, 
e.  g.)  are  deprived  of  their  branchiae,  they  will  aerate  blood  by 
the  lungs  exclusively,  and  there  is  no  reason  to  doubt  that  by  use 
of  these,  and  disuse  of  the  branchiae,  aerial  respiration  might  be- 
come the  habit  of  the  animal.  It  is  also  easy  to  perceive  that  geo- 
logic changes  would  bring  about  a  necessity  for  precisely  this  change 
of  habit.  This  occurred  in  the  period  of  the  coal  measures,  where 
large  fresh-water  areas  were  desiccated,  and  it  was  precisely  at  this 
period  that  many  air-breathing  Batrachians  originated  and  had  a 
great  development. 

j3.  The  rattle  of  the  Rattlesnake. — Nearly  all  the  larger  harm- 
less snakes  which  live  on  the  ground  have  a  habit  of  throwing  the 
end  of  the  tail  into  violent  vibrations  when  alarmed  or  excited, 
with  the  view  of  alarming  a  supposed  enemy.  Among  Coronelline 
snakes,  Ophiholus  triangulus  possesses  it ;  among  the  water  snakes, 
Tropidonotus  sipedon.  In  the  typical  Colubrine  group  the  black 
snake,  Bascanium  constrictor,  is  an  example  ;  Pityophis  sayi  also 
shakes  the  tail  violently.  The  copperhead  {Ancistrodon  contor- 
trix)  and  the  moccasin  {A.  piscivorus)  (fide  Giinther)  have  the 
habit  in  a  marked  degree.  Among  the  rattlesnakes  it  is  a  means 
of  both  warning  and  defense,  in  connection  with  the  rattle  which 
they  carry. 

In  the  structure  of  the  end  of  the  tail  of  harmless  snakes,  we 
see  a  trace  of  the  first  button  of  the  rattle  in  a  horny  cap  that  covers 
the  terminal  vertebrae.  In  the  venomous  genera,  it  is  conspicuous 
in  Lachesis  especially,  reaching  a  considerable  length  and  having 
a  lateral  groove.  In  the  plate-headed  rattlesnakes  (Crotalus)  this 
corneous  cap  is  inflated  into  a  button  with  lateral  groove,  and  in 
some  of  them  possesses  only  one  or  two  buttons  or  joints.  In  the 
perfected  rattlesnakes  {Gaudisona)  not  only  are  the  segments  nu- 
merous and  inflated,  but  a  number  of  the  terminal  caudal  vertebra? 
are  greatly  enlarged  vertically,  and  co-ossified  into  a  mass.*  This 
is  important  from  the  fact  that  the  rattlesnakes  are  the  most  spe- 


*  See  good  figures  of  this  structure  in  *'  Zeitschr.  f.  wissensch.  Zoologic,"  viii, 
Tab.  12. 


198  GENERAL  EVOLUTION. 

cialized  of  all  snakes,  standing  at  the  head  of  the  order,  and  as 
such,  on  the  principle  of  acceleratio7i,  present  the  greatest  amount 
of  grade-nutrition. 

Now  it  appears  to  me  that  the  constant  habit  of  violent  vibra- 
tion in  a  part  tends  to  determine  an  increased  amount  of  nutritive 
fluid  to  it,  in  other  words  to  localize  growth-nutrition,  and  when 
this  has  attained  complex  repetition  or  grade-nutrition,  to  result 
in  new  grade-structure.  (The  segments  of  the  rattle  being  nearly 
all  alike,  it  is  a  case  of  simple  repetition.)  This  view  appears  to 
be  as  reasonable  as  that  generally  entertained  with  regard  to  the 
cause  of  spavin  in  the  horse's  leg.  Here,  owing  to  excessive  use, 
exostoses  appear  on  the  bones  surrounding  the  tibio-tarsal  articula- 
tion. As  to  the  reason  of  tbe  structure  in  question  not  appearing 
in  forms  lower  in  the  scale  than  the  rattlesnake,  it  is  explained 
below,  if  the  law  of  accumulation  of  grade-nutrition  be  true.  (See 
Sec.  B.)  This  is,  that  repetition  (or  acceleration)  is  only  possible 
where  the  animal  has  an  excess  of  growth-force  at  its  disposal,  or 
can  abstract  it  from  some  portion  which  is  unused  or  useless. 

y.  On  horns. — The  possession  of  horns  on  the  posterior  part 
of  the  cranium,  as  defenses  against  enemies,  is  a  character  found 
in  many  distinct  types  of  animals.  (Herbivora  have  no  (dental) 
weapons  and  need  horns.)  It  is  seen  in  the  Batracliia  Stego- 
cephala  in  the  extinct  genus  Ceraterpeton ;  among  ^?^^^r«  it  is 
approached  by  Triprion  and  Hemiplir actus.  Among  Reptilia  it 
is  well  marked  in  PTirynosoma,  a  Lacertilian  genus.  In  Mamma- 
lia the  Artiodactyla  Ruminantia  are  the  horned  animals  of  the 
order.  We  have  opportunities  of  observing  the  habits  of  these 
representatives  of  the  Frogs,  the  Lizards,  and  the  Mammals. 

In  the  first  case,  any  one  who  has  kept  ordinary  toads  and 
tree-toads  in  confinement,  is  aware  that  when  attacked  and  unable 
to  escape,  they  defend  themselves  by  presenting  the  top  of  the 
head  forward  and  using  it  as  a  shield.  Now  I  have  already 
pointed  out  *  that  in  both  toads,  tree-toads,  and  frogs  there  are 
natural  series  of  genera,  measured  by  the  degree  of  ossification  of 
the  superior  cranial  walls,  the  longest  being  that  of  the  Hylidse, 
which  embraces  six  terms,  viz.  :  Hylella,  Hyla,  Scytopis,  Osteo- 
ceplialus,  Trachycephalus,  and  Triprion.  The  two  last  have  the 
head  thoroughly  shielded,  and  Hemipliractus  has  projecting  an- 
gles which  appear  in  some  South  American  forms,  described  bv  M. 


*  "  Origin  of  Geaera,"  1868,  p.  14.     This  work,  article  L 


THE   METHOD   OF  CREATION   OF   ORGANIC  FORMS.     199 

Espada,  to  be  developed  into  short  horns.  That  this  excessive 
ossification  is  associated  with  the  habit  of  protecting  the  whole 
body  with  the  front  seems  likely. 

In  the  case  of  Phrynosoma  we  know  that  precisely  the  same 
habit  is  associated  with  the  presence  of  the  sharp  horns  ;  and  that 
some  genera  without  horns  possess  it  also.  Phrynosoma  is  an  ex- 
ceptionally sluggish  genus  in  a  family  of  most  active  forms,  and 
must  necessarily  resort  to  this  mode  of  defense  more  than  they. 

In  the  case  of  Ruminants,  we  also  know  that  defense  is  accom- 
plished by  throwing  the  head  down  with  the  horns  thrown  for- 
ward. But  this  is  not  confined  to  this  group.  That  generalized 
suborder,  the  Artiodactyla  Omnivora,  represented  by  the  hog, 
which  were  no  doubt  the  genetic  predecessors  of  the  Euminants 
in  time,  also  throw  the  head  down  in  defense  in  the  same  way, 
having  thus  a  manner  totally  distinct  from  that  seen  in  the  Car- 
nivora.  The  latter  show  their  teeth  and  often  crouch  prepara- 
tory to  a  leap. 

These  cases  present  so  constant  an  association  between  habit 
and  use  that,  admitting  evolution,  we  are  compelled  to  believe 
that  the  structure  has  given  rise  to  the  habit  or  the  habit  to  the 
structure.  In  the  former  case  we  have  to  suppose,  with  the  au- 
thor of  ^'  Katural  Selection,"  that  among  the  many  spontaneous 
variations  rudimental  horns  occasionally  appeared,  and  that  their 
possessors,  being  thus  favored  in  the  struggle  for  existence,  were 
preserved  and  multiplied  ;  while  those  not  favored  dwindled,  and 
were  ultimately  nearly  all  extirpated  or  starved.  The  question 
of  origin  is  here  left  to  chance,  and  Alfred  Bennett  has  made  a 
mathematical  estimate  of  the  chances  of  any  particular  profitable 
variation  occurring  among  the  great  number  of  possibilities  of  the 
case.  This  has  shown  the  chance  to  be  so  excessively  small  as  to 
amount  in  most  cases  to  a  great  improbability. 

If  we  turn  to  the  probabilities  of  such  structure  having  arisen 
through  the  selection  of  that  mode  of  defense  by  the  animal,  we 
find  them  greatly  increased.  The  position  occupied  by  the  horns, 
in  all  the  animals  described,  is  that  which  is  at  once  brought  into 
contact  with  an  enemy  in  conflict,  and  as  sport  among  animals  is 
a  gentle  imitation  of  conflict,  the  part  would  be  constantly  excited 
in  sport  as  well.  With  an  excess  of  growth-nutrition,  our  knowl- 
edge of  the  effects  of  friction  on  the  epidermis,  and  of  excessive 
ligamentous  strain  and  inflammation  on  bone  (e.  g.,  spavin  in 
horses),  as  well  as  of  abnormal  exostoses  in  general,  would  warrant 


200  GENERAL  EYOLUTION. 

US  in  the  belief  that  the  use  of  the  angles  of  the  parts  in  question 
in  these  animals  would  result  in  a  normal  exostosis,  of  a  simple 
kind  in  the  frogs,  or  as  horn  cores  in  the  Euminantia.*  As  to  the 
sheathing  of  the  cores  in  the  Bovidce,  and  nakedness  in  the  Cer- 
vidcB,  it  is  in  curious  relation  to  their  habitat  and  to  their  habits. 
The  epidermis  and  derm  would  of  course  share  in  the  effects  of 
friction.  In  the  Bovidae  which  dwell  in  treeless  plains,  or  feed 
on  the  grasses  in  great  i:)art,  the  development  of  these  coverings  of 
the  horn  cores  into  a  horny  sheath  would  naturally  meet  with 
no  interruption.  In  the  case  of  the  deer,  which  mostly  live  in 
forests  or  browse  on  trees,  constant  contact  with  the  latter  would 
prevent  the  healthy  growth  of  the  dermal  covering,  and  it  would 
be  liable  to  injury  or  constant  excoriation  by  the  animals  them- 
selves on  the  branches  of  trees,  etc.  This  we  know  to  be  the  pres- 
ent habit  of  the  deer  as  regards  the  dermal  covering  of  the  horns. f 
I  have  elsewhere  pointed  out  the  similar  connection  between  the 
dental  structure  and  habitat  among  the  oxen  and  the  deer.  The 
former,  eating  the  harder  grasses,  are  provided  against  the  conse- 
quent rapid  attrition  of  the  tooth  by  a  prismatic  form,  which 
allows  of  more  prolonged  growth  and  more  rapid  protrusion. 
The  deer,  in  accordance  with  their  foliage-eating  habits,  do  not 
wear  the  crown  of  the  tooth  with  such  rapidity.  Long-continned 
protrusion  is  not  so  necessary,  hence  the  teeth  are  more  distinctly 
rooted  and  have  a  prominence  or  shoulder,  distinguishing  the 
body  of  the  crown. 

B.   Change  in  Amount  of  Groioth- Force. 

1.  Absolute  increase  of  Groiutli- Force. — As  every  type  has  had 
its  period  of  greatest  development  in  numbers,  size,  and  complica- 
tion of  structure,  the  present  law  indicates  as  an  exjolanation,  a 
culmination  of  the  process  of  conversion  of  growth-force  from  its 
energetic  to  its  potential  state  in  tissue.  The  cause  is  primarily 
the  increased  exercise  of  effort  and  use,  which,  while  effecting  a 
conversion,  increases  the  capacity  of  the  organs  by  which  further 
conversion  is  effected. 

*  The  now  well-known  fact  that  all  cranial  ossification  was  primitively  dermal, 
is  confirmatory  of  the  idea  that  its  appearance  was  due  to  moderate  friction  of  the 
skin  on  resistant  bodies.     (Ed,  1886.) 

f  Palaeontological  studies  go  far  to  show  that  the  origin  of  the  shedding  of  the 
deer's  horn  was  due  to  the  loss  of  their  dermal  covering,  and  that  this  was  caused  by 
violent  use.     (1886.) 


THE  METHOD   OF   CREATION   OF   ORGANIC  FORMS.     201 

2.  Local  increase  of  Growth-Force.— Bxam-phs  of  a  local  in- 
crease of  this  kind  are  probably  to  be  seen  in  conyoluted  organs  ; 
as  the  convolutions  of  the  brain  in  higher  Mammalia  ;  the  convo- 
lutions of  the  tooth-dentine  of  the  Labyrinthodont  Batrachia  ;  the 
same  phenomenon  in  the  cotyledons  or  plumule  of  some  seeds.  In 
these  cases  the  superficial  area  of  the  parts  is  excessively  developed, 
and  the  inclosing  organs  not  being  proportionately  enlarged,  a 
convolution  necessary  follows.  In  the  first  case,  the  skull ;  in  the 
second,  the  alveolus  ;  in  the  third  case,  the  seed-envelope,  restrain 
the  expanse  of  the  contained  part,  which  would  otherwise  follow 
increase  of  growth-force. 

3.  Absolute  loss  of  Growth-Force.— This  will  follow  defective 
nutrition,  produced  by  inability  of  the  animal  to  obtain  heat  and 
food  requisite  to  that  end.  This  is  supposed  to  be  due,  according 
to  the  view  hereafter  proposed,  primarily  to  deficiency  of  intelli- 
gence, in  failing  to  adapt  habits  to  changed  physical  circumstances, 
and  secondarily  to  the  unfavorable  influence  of  such  changed  cir- 
cumstances. The  extinction  of  highly  specialized  types,  which 
has  closed  so  many  lines  of  animal  types,  will  be  accounted  for  by 
their  less  degree  of  plasticity  and  want  of  capacity  for  change  un- 
der such  changed  circumstances.  Such  changes  consist  of  modified 
topography  and  temperature,  with  irruptions  of  many  new  forms 
of  life  by  migration.  The  less  developed  forms  would  be  most 
likely  to  experience  modification  of  structure  under  a  new  order 
of  things,  and  paleontology  teaches  that  the  predecessors  of  the 
characteristic  types  of  one  period  were  of  the  less  specialized  forms 
of  that  period  which  went  before. 

Thus  is  explained  the  fact  that,  in  following  out  the  line  of 
succession  of  animal  forms,  we  have  constantly  to  retrace  our  steps 
from  specialized  extremes  (as  osseous  fishes,  tailless  Batrachia, 
song  birds,  etc.)  to  more  generalized  or  simple  forms,  in  order  to 
advance  beyond. 

4.  The  complementary  dimimitioii  of  growth-nutrition  follows 
the  excess  of  the  same  in  a  new  locality  or  organ,  of  necessity,  if 
the  whole  amount  of  which  an  animal  is  capable  be,  as  I  believe, 
fixed.  In  this  way  are  explained  the  cases  of  retardation  of  char- 
acter seen  in  most  higher  types.  The  discovery  of  truly  comple- 
mentary parts  is  a  matter  of  nice  observation  and  experiment. 
Perhaps  the  following  cases  may  be  correctly  explained. 

A  complementary  loss  of  growth-force  may  be  seen  in  absence 
of  superior  incisor  teeth  and  digits  in  ruminating  Mammalia,  where 


202  GENERAL  EVOLUTION". 

excessive  force  is  evidently  expended  in  the  development  of  horns, 
and  complication  of  stomach  and  digestive  organs.  The  excess 
devoted  to  the  latter  region  may  account  for  the  lack  of  teeth  at 
its  anterior  orifice,  the  mouth  ;  otherwise,  there  appears  to  be  no 
reason  why  the  ruminating  animals  should  not  have  the  superior 
incisors  as  well  developed  as  in  the  odd-toed  (Perissodactyl)  Un- 
gulates, many  of  which  graze  and  browse.  The  loss  to  the  osseous 
system  in  the  subtraction  of  digits  may  be  made  up  in  the  develop- 
ment of  horns  and  horn-cores,  the  horn  sheath  being  perhaps  the 
complement  of  the  lost  hoofs.  It  is  not  proposed  to  assert  that 
similar  parts  or  organs  are  necessarily  and  in  all  groups  comple- 
mentary to  each  other.  The  horse  has  the  bones  of  the  feet  still 
further  reduced  than  the  ox,  and  is  nevertheless  without  horns. 
The  expenditure  of  the  complementary  growth-force  may  be  sought 
elsewhere  in  this  animal.  The  lateral  digits  of  the  Equidce  are 
successively  retarded  in  their  growth,  their  reduction  being  marked 
in  Hiypotlierium,  the  last  of  the  three-toed  horses ;  it  is  accom- 
panied by  an  almost  coincident  acceleration  in  the  growth-nutri- 
tion of  the  middle  toe,  which  thus  ajipears  to  be  complementary 
to  them. 

The  superior  incisors  of  the  Artiodadyla  disa^Dpear  coincident- 
ally  with  the  appearance  of  horns,  which  always  exist  in  the  tooth- 
less division  of  the  order,  excej)t  in  some  very  small  antelopes 
(Cephalophus,  etc.)  where  the  whole  amount  of  growth-force  is 
small.  Possibly  the  superior  incisors  and  horns  are  complementary 
here.  The  retardation  in  development  of  the  teeth  in  the  higher 
apes  and  men,  as  compared  with  the  lower  apes,  is  coincident  with 
the  increase  of  number  of  brain  convolutions.  That  this  is  not 
necessarily  coincident  with  reduction  of  teeth  in  other  groups  is 
plainly  proved  by  the  rodents  and  CMromys,  where  the  loss  of  many 
teeth  is  complementary  to  the  great  size  of  the  incisors  of  the  mid- 
dle pair.  But  in  man  there  is  no  complementary  increase  of 
other  teeth,  and  the  reduction  is  no  doubt  due  to  contraction  of 
the  jaws,  which  is  complementary  to  increase  in  other  parts  of  the 
cranium,  in  both  apes  and  men. 

I  am  confident  that  the  origin  and  loss  of  many  structures  may 
be  accounted  for  in  this  way,  and  the  correlation  of  parts  to  each 
other  be  measured  accurately. 

Objection, — The  first  one  which  arises  is  that  which  the  author 
of  the  ^^  Vestiges  of  Creation  "  made  against  Lamarck's  theory  of  a 
similar  kind,  i.  e.,  that  by  assuming  that  effort,  use,  and  physical 


THE  METHOD   OF  OREATIO]^   OF   ORGANIC  FORMS.     203 

causes  have  originated  modifications  of  structure,  we  give  the 
adaptive  principle  too  much  to  do.  I  have  made  the  same  objec- 
tion to  the  theory  of  natural  selection.  It  is  true  that  an  ai^plica- 
tion  to  a  purpose  is  involved  in  the  present  theory  of  the  'location 
of  growth-force  "  ;  but  in  point  of  fact,  a  large  number  of  non- 
adaptive  characters  are  accounted  for  by  it.  These  are  the  rudi- 
mental  and  transitional  ones  which  mark  the  successive  steps  pre- 
liminary to  the  completion  of  an  adaptive  structure ;  second,  those 
produced  by  deficiency  of  growth-force  in  less  favored  regions  of 
the  body  ;  and  third  and  fourth,  phenomena  consequent  on  general 
deficiency  and  excess  of  growth-force. 

And  it  may  be  said  in  conclusion  that  if  the  three  principles, 
or  if  use  especially,  should  be  found  to  be  inadequate  to  the  service 
here  demanded  of  them,  it  may  be  at  least  said  that  they,  or  the 
last  named,  constitute  the  only  controllers  of  growth-force  to  any 
degree  at  all  with  which  we  are  acquainted. 

lY.   01^   GKADE-IKFLUE5^CE. 

The  object  of  the  present  section  is  the  attempt  to  discuss  how 
the  influence  of  effort  and  use  on  the  parent  is  placed  in  a  position 
to  be  inherited  by  the  offspring. 

A.  Of  the  Nature  of  Grade-Lifluence. 

In  the  first  place,  it  is  necessary  to  note  the  definition  and  char- 
acter of  grade-influence. 

a.  Growth- force  uninfluenced  by  grade-influence  simply  adds 
tissue  either  {a)  in  enlarging  size,  or  {b)  in  rejilacing  waste.  It 
does  this  by  repeating  the  cell,  by  division,  in  localities  which  have 
already  assumed  their  specific  form.  This  form  of  growth-force 
may  persist  throughout  life,  but  with  diminished  energy  in  age. 

(i.  Grade-influence  directs  growth-force  in  building  up  the  tis- 
sues into  organs,  and  constructs  the  parts  of  the  body  successively 
to  completion,  the  result  expressing  the  type  or  grade  of  the  ani- 
mal or  plant.  Its  energy  terminates  with  maturity,  except  in 
cases  of  periodical  reproduction  of  sexual  ornaments  of  the  male 
(birds,  deer),  where  it  continues  throughout  life,  appearing  at 
regular  intervals. 

But  it  has  occurred  in  acceleration  that  instead  of  a  simple  repe- 
tition of  the  ultimate  histological  element  of  an  organism,  in  add- 
ing to  its  amount,  it  adds  a  completely  organized  part  of  the  struct- 


204  GENERAL  EVOLUTION. 

ure,  as  a  tube,  a  phalange,  a  digit,  a  limb  or  an  arch  ;  an  ocellus 
or  a  tooth.  For  instance,  in  the  genus  Amhlystoma,  one  section 
possesses  four  phalanges  on  the  longest  digit ;  another  section 
exhibits  but  three.  In  the  species  A,  mavortium,  some  individuals 
have  the  small  number  of  phalanges,  but  the  majority  possess  the 
larger  number.  As  all  are  of  common  parentage,  a  whole  phalange 
has  been  lost  or  added.  The  explanation  of  this  phenomenon  is 
essential  to  the  comprehension  of  the  origin  of  type  structures. 

*  In  plants,  growth-nutrition  continues  throughout  life,  but  in 
the  higher  plants  it  is  more  active  during  the  earlier  years  in  peren- 
nial species,  addition  to  size  becoming  less  and  less  marked  with 
increasing  age.  Grade-nutrition  also  persists  throughout  life,  but 
is  chiefly  active  during  a  short  period  only  of  every  year,  or  during 
flowering  and  fruiting.  Not  only  in  the  production  of  the  repro- 
ductive organs,  but  also  in  the  yearly  additions  to  other  tyj^ical 
parts  of  the  plant,  grade-nutrition  is  active. 

**  In  animals,  growth-nutrition  is  more  active  in  the  early 
stages  of  life,  but  is  continued  throughout  in  the  lower  divisions  ; 
in  the  highest,  it  is  also  continued  throughout  life,  but  there  is  a 
greater  contrast  between  its  results  during  youth,  when  nearly  the 
whole  size  is  attained,  and  during  age,  where  the  additions  are 
much  less. 

Grade-nutrition  is,  on  the  other  hand,  entirely  confined  to  in- 
fancy and  youth,  except  in  those  low  animals  which  produce  their 
reproductive  organs  periodically  (some  Fntozoa,  etc.),  where  it  may 
be  said  to  be  in  nearly  the  same  condition  as  in  plants. 

y.  While  the  amount  of  simple  growth-force,  represented  in 
adult  living  animals,  has  varied  very  irregularly  throughout  the 
animal  kingdom,  there  being  large  and  small  in  every  division,  it 
would  seem  to  have  accumulated,  on  the  whole,  with  the  rising 
scale  of  animal  types.  Thus  the  lower  or  Protozoa  are  the  small- 
est ;  Radiates  are  next  in  size  ;  Molluscs  and  Articulates  reach 
nearly  the  same  maximum,  which  exceeds  that  of  the  Radiates, 
and  falls  far  below  that  of  the  Vertebrates.  Among  the  last  the 
Mammalia  have  attained  as  large  if  not  larger  size  than  any  of  the 
other  orders  (e.  g.,  Cetaced).  This  is,  however,  not  necessary  to 
the  history  of  evolution. 

That  an  increased  amount  of  grade  growth-force  has  been  con- 
stantly rendered  potential  during  the  advance  of  time  is  clear,  if 
the  preceding  inferences  be  true.  It  is  also  evident  that  some  in- 
dividuals have  accumulated  it  more  rapidly  than  others.  If  all 


THE  METHOD  OF  CREATION  OF  ORGANIC  FORMS. 


205 


alike  originated  from  the  simplest  forms  known  to  us.  Multi- 
tudes have  remained  in  the  earliest  stages  {Protozoa)  of  the  whole 
series,  or  of  their  own  special  series  {Lingula),  forming  *' persist- 
ent types  "  ;  or  taken  directions  which  rendered  them  incapable 
of  expansion  beyond  a  certain  point  without  exhaustion  or  death  ; 
for  example,  complicated  types,  as  Ammonitidcs.  The  quadruma- 
nous  animal,  which  was  the  progenitor  of  man,  may  thus  be  be- 
lieved to  have  acquired  a  higher  capacity  of  this  accumulation 
than  his  contemporaries. 

Assuming  the  nucleated  cell  to  be  the  ultimate  element  of  or- 
ganic tissue,  there  are  two  types  of  hfe  in  which  grade-influence 
has  not  appeared,  viz. :  unicellular  animals  and  plants,  and  living 
forms  composed  of  homogeneous  protoplasm.  In  the  latter  neither 
grade-influence  nor  animal  growth-force  is  potential ;  in  the  for- 
mer, simple  growth-force  only.  It  is  therefore  apparent  that  grade- 
influence  has  been  developed  in  the  organism  itself  ;  perhaps  this 
may  have  been  in  the  plant,  through  the  modified  influence  of  ex- 
ternal physical  causes  ;  in  the  animal,  if  our  inductions  as  to  use 
and  effort  be  true,  under  the  influence  of  the  activities  of  the  par- 
ent, which  determined  a  structural  change  either  in  itself  or  in 
its  offspring.  The  possibilities  of  this  origin  are  considered  in  the 
next  section. 

8.  The  Location  of  Growth-Force  proceeds  under  the  direction 
of  what  Prof.  Henry  calls  "Vital  Influence."  With  this  author  I 
discard  the  use  of  the  term  "Vital  Force,"  what  was  originally 
understood  by  that  term  being  a  complex  of  distinct  ideas.  The 
Vital  forces  are  (nerve-force)  Neurism,  (growth-force)  Bathnism, 
and  (thought-force)  Plirenism.'^  All  these  are  supposed  to  be 
correlated  to  the  Physical  Forces,  but  are  under  direction  and 
control  of  the  Vital  principle  which  locates  their  action,  etc.,  just 
as  molecular  or  atomic  constitution  determines  the  locality  and 
character  of  the  physical  forces.  The  laws  of  the  vital  principle 
and  of  atomic  constitution  also  determine  the  nature  of  the  con- 
version of  one  force  into  another.  Now,  since  physical  and  vital 
forces  are  correlated  and  convertible,  the  close  relationship  of  the 
two  controlling  principles  becomes  obvious  and  suggestive  of  their 
identity. 

*  The  objection  of  President  Barnard  to  thought  being  an  exhibition  of  a  force, 
is  that  "  thought  can  not  be  measured."  This  objection  docs  not  take  into  consid- 
eration the  two-fold  nature  of  thought.  The  amount  of  thought  can  most  assuredly 
be  measured,  the  quality  of  the  thought  can  not. 


206  GENERAL  EVOLUTION. 

Dr.  Carpenter,  in  describing  the  correlation  of  j)hysical  and 
vital  forces,  defines  the  difference  of  organic  species  to  be  similar 
to  that  prevailing  between  different  chemical  bodies  (the  latter 
depending  on  different  molecular  and  atomic  constitution),  which 
leads  them  "  to  'behave  differently"  from  each  other  under  simi- 
lar circumstances.  This  may  be  more  fully  expressed  by  saying 
that  different  species  possess  different  capacities  for  the  location 
of  the  conversion  of  the  physical  forces  into  growth-force.  A 
"  descent  with  modifications  "  contemplated  by  a  process  of  evolu- 
tion, signifies  a  progressive  change  in  this  capacity.  Acceleration 
means  an  increase  in  this  capacity  ;  retardation  a  diminution  of 
it.  Grade-infiuence  means  the  influence  which  produces  this 
change  of  capacity. 

B,   The  Origin  of  Grade-Injiuence. 

Living  protoplasm  can  convert  heat  and  nutriment  into 
growth-force  without  the  agency  of  the  nervous  system.  This 
is  proved  by  the  nutrition  of  the  Protozoa  and  Ccelenterata,  and 
from  experiments  on  the  muscles  of  frogs,  etc.  In  the  latter  case, 
as  is  well  known,  the  nerve  may  be  divided,  and  the  muscle  retain 
its  size  if  a  current  of  electricity  be  passed  through  it,  thus  sus- 
taining the  nutrition.  As  the  presence  and  structure  of  the  nerv- 
ous system  is  in  relation  to  the  specialization  of  animal  struct- 
ure in  other  respects,  it  is  very  probable  that  the  nervous  system  is 
in  higher  animals  the  agent  of  the  location  of  growth -force.  In 
the  lowest  it  is  not  affected  by  any  such  means.  As  the  nervous 
system  is  the  instrument  of  the  metaj^hysical  peculiarities  of  the 
animal  (emotions,  choice,  etc.),  we  may  conclude  that,  in  the 
lower  animals,  location  of  growth-force  is  influenced  by  necessity 
without  choice  ;  in  the  higher  by  necessity  with  choice. 

The  impulses  derived  from  the  nervous  system,  it  is  known, 
may  be  reflex  or  automatic  in  answer  to  stimuli  from  without. 
They  may  become  so,  also,  after  having  been  originated  conscious- 
ly or  by  effort  of  will.  In  the  case  of  habits,  frequent  exercise  of 
choice  has  so  impressed  the  nervous  system  as  to  result  in  its 
repetition  of  effort,  often  in  opposition  to  changed  choice. 

The  influence  of  effort  in  muscular  action,  through  the  nervous 
system,  appears  to  be,  first,  to  enable  it  to  convert  heat  to  nerve- 
force,  and,  then,  to  conduct  nerve-force  to  the  involuntary  mus- 
cles, or  those  controlling  circulation,  where  it  is  converted  into 
motion,  which  thus  controls  nutrition  throuirh  circulation.     The 


THE  METHOD   OF  CREATION  OF  ORGANIC  FORMS.    207 

nervous  system,  like  others,  develops  in  capacity  with  use,  hence 
probably  nerve-tissue  converts  heat  *  into  nerve-force  as  muscular 
tissue  converts  heat  into  motion.  In  other  words,  by  repetition, 
the  capacity  of  the  nervous  system  for  this  conversion  of  heat  is 
known  to  increase.  As  the  amount  of  heat  converted  is  in  pro- 
portion to  the  amount  of  appropriate  nerve-tissue  (see  above),  it  is 
evident  that  use  and  effort  increase  the  amount  of  nerve-tissue. 

The  phenomena  of  thought  render  the  same  modification  of 
structure  j)robable.  Effort  in  the  direction  of  thought  is  supposed 
to  convert  heat  into  thought-force.  Inasmuch  as  the  more  intelli- 
gent animals  possess  the  highest  development  of  cerebral  hemi- 
spheres, it  is  highly  probable  that  brain  substance  converts  heat 
into  growth-force  also,  which  produces  tissue  of  its  own  kind  pre- 
cisely as  muscle  does. 

As  different  parts  of  the  nervous  centers  subserve  different 
purposes,  the  development  of  these  parts  must  proceed  approxi- 
mately under  the  influence  of  special  kinds  of  effort  and  use. 
Where,  as. in  the  adult,  heat  is  converted  into  growth-force  in  the 
tissues  to  a  very  limited  extent,  if  the  above  principles  be  true, 
the  conversion  of  heat  by  the  nervous  system  into  nerve  growth- 
force  and  tissue  is,  on  the  other  hand,  not  terminated. 

Capacity  for  effecting  conversion  of  force  is  regarded,  as  above 
pointed  out,  as  dependent  on  molecular  constitution.  Hence  we 
conclude  that  change  in  that  capacity  on  the  part  of  the  nervous 
system  involves  a  molecular  change  in  its  constitution. 

Now,  we  know  physical  and  metaphysical  peculiarities  of 
parents  to  be  inherited  by  offspring  ;  hence,  no  doubt,  the  nervous 
structure  determinative  of  growth-force  is  inherited.  This  will 
then  control  the  localities  of  special  conversion  of  heat,  etc. 
(from  the  mother),  into  growth-force,  in  accordance  with  the 
structure  of  the  parent,  and  the  more  decidedly,  as  its  own  in- 
crease progresses. 

The  result  will  be  acceleration,  or  construction  of  tissues  and 
organs  in  excess  of  those  of  the  parent,  if  the  effort  or  use  de- 
voted to  a  nerve  or  organ  be  represented  in  the  nerve-center  of 
the  parent  by  a  greater  amount  of  force-converting  tissue  than  is 


*  The  supposition  that  this  and  other  forms  of  vital  energy  are  derived  from 
metamorphosis  of  heat,  was  in  accordance  with  views  held  at  the  time  this  essay 
was  written  (1871).  The  much  more  probable  hypothesis  is  that  such  energy  is 
derived  from  retrograde  metamorphosis  of  nutritive  material.     (Ed.  1886.) 


208  GENERAL  EVOLUTIOI^. 

necessary  when  inherited  in  the  foetus  for  the  construction  (by 
conversion)  of  tissues  and  organs  like  those  of  the  parent. 

,y^  That  this  is  a  partial  explanation  of  inheritance,  is  rendered 
probable  from  the  fact  that  the  types  of  structure  presented  by 

\  the  nervous  centers  express  the  grade  of  the  animals  possessing 
them  far  more  nearly  than  those  of  any  other  organ  or  set  of  or- 
gans. If  the  brain,  like  other  organs,  develops  by  intelligent  use, 
it  can  not  be  doubted  that  this  relation  of  its  development  to 

I  grade  is  not  accidental,  but  that  grade-structure  *  is  an  expression 
of  its  capacities,  physical  and  mental. 

V.  o:n"  intelligent  selection. 

As  neither  nse  nor  effort  can  be  ascribed  to  plants,  and  as  we 
know  that  their  life  history  is  much  more  dependent  on  their  sur- 
roundings than  is  that  of  animals,  we  naturally  look  to  the  physi- 
cal and  chemical  causes  as  having  a  prime  influence  in  the  origina- 
tion of  their  type-structures.  Without  greater  familiarity  with 
the  subject,  I  will  not  attempt  to  say  how  far  the  various  degrees 
of  growth-force  possessed  by  parent  plants,  located  under  the  influ- 
ence of  meteoric  and  other  surroundings,  and  preserved,  destroyed 
or  restricted  by  natural  selection,  may  account  for  the  characters 
of  their  successors  of  the  present  period.  But  other  agencies  simi- 
lar to  use,  that  is,  automatic  movements,  may  be  also  introduced 
as  an  element  in  the  argument.  The  movements  of  tendrils  seek- 
ing for  support  may  be  here  considered,  and,  as  Dr.  Asa  Gray  has 
pointed  out,  have  consequences  similar  to  those  of  use  in  animals. 
When  the  tendril  seizes  a  support,  growth-force  is  located  at  the 
point  of  contact,  for  the  tendril  increases  considerably  in  thick- 
ness. 

Among  animals  of  the  lowest  grade,  movement  must  be  quite 
similar  to  those  of  plants,  or  automatic  from  the  start,  and  not 
even  at  the  beginning  under  the  influence  of  will.  Evidence  of 
will  is,  however,  soon  seen  in  the  determinate  movements  of  many 
of  the  Protozoa  in  the  seizing  of  food.  With  will  necessarily  ap- 
pears a  power  of  choice,  however  limited  in  its  lowest  exhibitions, 
by  the  lack  of  suggestive  metaphysical  qualities,  or  the  fewness  of 
alternatives  of  action  presented  by  surrounding  circumstances,  to 
animals  of  low  and  simple  organism.     We  can,  however,  believe 

^  Grade  growth-force  is  not  regarded  here  or  elsewhere  as  a  simple  form  of 
energy,  but  as  a  class  of  energies,  which  are  the  resultants  of  the  interference  of 
mind  (i,  e.,  consciousness)  with  simple  growth-force.     (Ed.  1886.) 


THE   METHOD   OF   CREATION   OF   ORGANIC  FORMS.     209 

that  the  presence  of  greater  or  less  number  of  external  facilities 
for  action  characterize  different  situations  on  the  earth's  surface, 
as  well  as  that  greater  and  less  metaphysical  capacity  for  perceiv- 
ing and  taking  advantage  of  them  must  exist  in  diiferent  indi- 
viduals of  every  species  of  animal,  however  low,  which  possesses 
consciousness  and  will.  These  qualities  must,  of  course,  influence 
eifort  and  use  to  the  advantage  of  the  animal,  or  the  reverse. 

Effort  and  use  have  very  various  immediate  stimuli  to  their 
exertion. 

Use  of  a  part  by  an  animal  is  either  compulsory  or  optional. 
In  either  case,  the  use  may  be  followed  by  an  increase  of  nutrition 
under  the  influence  of  reflex  action  or  of  direct  volition. 

A  compulsory  use  would  naturally  occur  in  new  situations 
which  take  place  apart  from  the  control  of  the  animal,  where  no 
alternatives  are  presented.  Such  a  case  would  arise  in  a  submerg- 
ence of  land  where  land-animals  might  be  imprisoned  on  an  island 
or  in  swamps  surrounded  by  water,  and  compelled  to  assume  a 
more  or  less  aquatic  life.  Another  case,  which  has  also  probably 
often  occurred,  would  be  when  the  enemies  of  a  species  should  so 
increase  as  to  compel  a  large  number  of  the  latter  to  combat  who 
had  previously  escaped  it. 

In  these  cases,  the  structure  produced  would  be  necessarily 
adaptive.  But  the  effect  would  sometimes  be  to  destroy  or  injure 
the  animals  (retard  them)  thus  brought  into  new  situations  and 
compelled  to  an  additional  struggle  for  existence,  as  has,  no 
doubt,  been  the  case  in  geologic  history. 

Direct  compulsion  would  also  exist  where  alternatives  should 
be  presented  by  nature,  but  of  which  the  animal  would  not  be 
sufficiently  intelligent  to  take  advantage. 

Most  situations  in  the  struggle  for  existence  afford  alterna- 
tives, and  the  most  intelligent  individuals  of  a  species  will  take 
advantage  of  those  most  beneficial.  Nevertheless,  it  is  scarcely 
conceivable  that  any  change  or  increase  of  effort,  or  use,  could 
take  place  apart  from  compulsion  derived  from  the  relation  of 
external  circumstances,  as  a  more  or  less  remote  cause. 

Preservation,  with  modifications,  would  most  probably  ensue 
when  change  of  stimulus  should  occur  gradually,  though  change 
of  structure  might  occur  abruptly,  under  the  law  of  expression 
points.  * 


*  See  "  Origin  of  Genera,"  p.  3S. 
14 


210 


GENERAL  EYOLUTIOX. 


Choice  is  influence  not  only  by  intelligence,  but  by  the  imagi- 
nation and  by  the  emotions. 

Intelligence  is  a  conservative  principle,  and  always  will  direct 
effort  and  use  into  lines  which  will  be  beneficial  to  its  possessor. 
Here  we  have  the  source  of  the  fittest — i.  e.,  addition  of  parts  by 
increase  and  location  of  growth-force,  directed  by  the  will — the 
will  being  under  the  influence  of  various  kinds  of  compulsion  in 
the  lower,  and  intelligent  option  among  higher  animals. 

Thus,  intelligent  choice,  taking  advantage  of  the  successive 
evolution  of  physical  conditions,  may  be  regarded  as  the  originator 
of  the  fittest,  while  natural  selection  is  the  tribunal  to  which  all 
the  results  of  accelerated  growth  are  submitted.  This  preserves 
or  destroys  them,  and  determines  the  new  points  of  departure  on 
which  accelerated  growth  shall  build. 

The  influences  locating  growth -force  may  be  tabulated  as 
follows  : 


DIVISION. 


INFLUENCE. 


Plants. 


Physical  and  ) 
chemical.     ^ 


+ 


9    9 


Plants  with  me- 
c  h  a  n  i  c  a  1  move- 
ments; animals 
with  indeterminate 
movements. 

Animals  with  de-  ^ 
terminate  move-  I 
ments  or  will,*  but  j 
no  intelligence.         J 

Animals  with 
will  and  less  intel- 
ligence. 

Animals  with 
more  intelligence. 


-h  use 


« 


-f-  effort  under 
compulsion. 


(( 


(( 


(( 


(( 


((  (( 


-f  choice. 


-I-  intelligent  choice. 


As  examples  of  intelligent  selection,  the  modified  organisms  of 
the  varieties  of  bees  and  ants  must  be  regarded  as  striking  cases. 
Had  all  in  the  hive  or  hill  been  modified  alike,  all  soldiers,  neu- 
ters, etc.,  the  origin  of  the  structures  might  have  been  thought  to 
be  compulsory  ;  but  varied  and  adapted  as  the  different  forms  are 
to  the  wants  of  a  community,  the  influence  of  intelligence  is  too 
obvious  to  be  denied. 

The  selection  of  food  offers  an  opportunity  for  the  exercise  of 


*  Will  must  be  here  regarded  as  the  answer  to  stimulus,  without  any  element  of 
freedom.     See  Article  XX,  on  the  "  Origin  of  the  Will."     (Ed.  1886.) 


THE  METHOD   OF   CREATION   OF  ORGANIC  FORMS.     211 

intelligence,  and  the  adoption  of  means  for  obtaining  it  still 
greater  ones.  It  is  here  that  intelligent  selection  proves  its  su- 
premacy as  a  guide  of  use,  and  consequently  of  structure,  to  all 
the  other  agencies  here  proposed.  The  preference  for  vegetable 
or  for  animal  food  determined  by  the  choice  of  individual  animals 
among  the  omnivores,  which  were,  no  doubt,  according  to  the 
paleontological  record,  the  predecessors  of  our  herbivores,  and  per- 
haps of  carnivores  also,  must  have  determined  their  course  of  life 
and  thus  all  their  parts,  into  these  totally  distinct  directions. 
The  choice  of  food  under  ground,  on  the  ground,  or  in  the  trees 
would  necessarily  direct  the  uses  of  organs  in  the  appropriate 
directions  respectively. 

In  the  selection  of  means  of  defense  a  minor  range  of  choice  is 
presented.  The  choice  must  be  limited  to  the  highest  capabilities 
of  the  animal,  since  in  defense,  these  will,  as  a  general  thing,  be 
put  forth.  This  will,  however,  not  be  necessarily  the  case,  but 
will  depend  in  some  measure  on  the  intelligence  of  the  animal,  as 
we  readily  observe  in  the  case  of  domesticated  species. 

In  the  case  of  the  rattlesnake,  already  cited,  the  habit  of  rapid 
vibration  of  the  tail  appears  to  me  to  be  the  result  of  choice,  and 
not  of  compulsion.  For  the  cobra  of  India,  for  the  same  pur- 
pose, expands  the  anterior  ribs,  forming  a  hood,  which  is  a  very 
different  habit.*  Here  are  two  alternatives,  from  which  choice 
might  be  made,  and  violent  hissing  is  a  third,  which  the  species 
of  the  colubrine  genus  Pityopliis  have  adopted  to  some  purpose. 
As  to  the  benefit  of  the  rattle,  it  no  doubt  protects  the  animal 
from  all  foes  other  than  man  ;  but  is  rather  a  disadvantage  as  re- 
gards the  latter,  being  by  a  beautiful  turn  of  events  a  protection 
to  the  higher  animal. 

On  the  principle  of  natural  selection  it  might  be  supposed  that 
the  harmless  snakes  which  imitate  the  Crotalus  for  the  sake  of 
defense  were  preserved  ;  but  if  the  above  explanation  of  the  origin 
of  the  habit  in  the  latter  be  true,  the  second  explanation  is  not 
valid.  (Since  in  time  the  harmless  snakes  preceded  the  rattle- 
snakes.    Ed.  1886.) 

The  power  of  metachrosis,  or  of  changing  the  color  at  will,  by 
the  expansion  under  nerve-influence  of  special  pigment  cells,  exists 
in  most  Reptilia,  Batrachia,  and  fishes.  It  is  then  easy  to  believe 
that  free  choice  should,  under  certain  circumstances,  so  habitually 

*  The  North  American  Heterodons  possess  a  similar  habit.     (Ed.  1S86.) 


212  GENERAL  EVOLUTION. 

avoid  one  or  another  color  as  to  result  finally  in  a  loss  of  the  power 
to  produce  it. 

Thus,  it  appears  to  be  a  fact  that  not  only  are  species  of  fishes 
which  dwell  in  the  mud  of  darker  hues  than  those  that  inhabit 
clear  water,  but  that  individuals  of  the  same  species  differ  in  a  simi- 
lar manner  in  relation  to  their  habitats  ;  those  that  live  in  impure 
or  muddy  waters  having  darker  tints  than  those  of  clear  streams. 

Land  animals  present  equally  abundant  and  remarkable  imita- 
tions of  the  objects  or  substances  on  which  they  live.  This  is 
well  known  in  insects  and  spiders,  which  look  like  sticks  or 
leaves,  or  the  flowers  on  which  they  feed.  It  is  seen  in  reptiles, 
which  in  very  many  cases  can  voluntarily  assume  the  hue  of  leaf, 
stone,  or  bark,  or  have  constantly  the  gray  color  of  their  native 
desert  sands. 

These  cases  are  largely  selective  or  optional  in  their  origin,  for 
though  metachrosis  is  also  induced  by  some  external  stimulus,  as 
an  enemy  or  a  food  animal,  yet  other  means  of  escaj)ing  the  one 
and  procuring  the  other  are  generally  open. 

These  facts  pave  the  way  for  a  consideration  of  the  phenome- 
non of  mimetic  analogy,  which,  though  well  known  to  naturalists, 
may  be  illustrated  by  the  following  new  facts  : 

On  the  plains  of  Kansas  there  is  a  species  of  Mutilla  whose 
abdomen  and  thorax  are  colored  ochraceous,  or  brown-yellow, 
above.  A  spider  of  the  genus  SaUicus  is  equally  abundant,  and 
is  almost  j)recisely  similar  in  the  color  of  the  upper  surfaces,  so 
much  so  as  to  deceive  any  but  a  most  careful  observer.  The 
Mutilla  being  a  well-armed  insect,  and  a  severe  stinger,  there  can 
be  no  doubt  that  the  SaUicus  derives  considerable  immunity  from 
enemies  from  its  resemblance. 

On  the  same  plains,  the  Crotalus  conjiuentus,  or  prairie  rattle- 
snake, abounds.  It  is  an  olive  gray,  with  a  series  of  transverse 
brown  dorsal  spots,  and  two  rows  of  smaller  lateral  ones.  The 
head  exhibits  a  number  of  brown  and  white  bands.  The  prairie 
Heteroclon  {H.  nasicus)  possesses  not  only  the  same  tints  but  the 
same  pattern  of  coloration,  and  at  a  short  distance  can  not  be  dis- 
tinguished from  it. 

In  consequence,  as  one  may  justly  say,  this  species  is,  with  the 
rattlesnake,  the  most  common  serpent  of  the  plains,  as  it  shares, 
no  doubt,  in  the  protection  which  the  armature  of  the  Caudisona 
gives  its  possessor.  This  is  in  accordance  with  the  views  of  Wal- 
lace and  Bates. 


THE  METHOD   OF  CREATION  OF  ORGANIC  FORMS.    213 

A  curious  case  occurred  to  me  in  four  species  of  fishes,  which 
I  took  in  a  small  tributary  of  the  Yadkin  River,  in  Roane  County, 
N.  0,  Among  several  others,  there  were  varieties  of  the  widely 
distributed  species  Chaenohryttus  viridis,  Hypsilepis  analostanus, 
and  Ptychostomus  pidie7isis  (each  representing  a  different  family), 
which  differ  from  the  typical  form  of  each  in  the  same  manner, 
viz. :  in  having  the  back  and  upper  part  of  the  sides  with  longi- 
tudinal black  lines,  produced  by  a  line  along  the  middle  of  each 
scale.  This  peculiarity  I  have  not  observed  in  these  species  from 
any  other  locality.  Until  I  had  examined  them  I  thought  them 
new  species. 

The  only  other  species  presenting  such  marking  in  the  Yadkin 
River  is  the  large  perch,  the  Roccus  lineatus.  According  to  the 
theory  of  natural  selection  a  resemblance  to  this  well-armed  species 
might  be  of  advantage  to  the  much  weaker  species  in  question  ; 
yet  the  same  species  co-exist  in  other  rivers  without  presenting 
the  same  mimicry. 

It  is  difficult  not  to  urge  the  importance  of  the  causes  already 
regarded  as  efficient  in  the  origination  of  structure  in  the  present 
branch  of  the  subject  also.  We  are  especially  disposed  to  call  in 
use  and  effort  here,  after  noticing  how  much  more  distinctly 
change  of  color  is  under  the  control  of  the  animal,  than  change  of 
shape.  It  must,  however,  be  borne  in  mind  that  similar  resem- 
blances exist  among  plants  ;  though,  as  Professor  Dyer  shows,  a 
large  majority  of  these  cases  occur  in  species  of  different  floral 
regions.  Thus  in  this  case,  as  in  those  of  structure  already  cited, 
we  appeal  first  to  physical  laws  in  the  lowest  beings,  but  with  the 
increasing  interference  of  use,  effort,  and  intelligence,  as  we  rise  in 
the  scale.  Thus  it  is  that,  in  the  Vertebrates  generally,  the  mi- 
metic resemblances  are  found  in  species  of  the  same  region,  where 
only  an  intelligent  or  emotional  agency  could  be  illustrated.  If 
among  animals  as  low  as  butterflies  the  influence  of  intelligence  be 
denied,  that  of  admiration  for  the  beauty,  or  fear  of  the  armature, 
of  the  predominant  species  imitated,  would  appear  to  be  sufficient 
to  account  for  the  result.  Admiration  and  fear  are  possessed  by 
animals  of  very  low  organization,  and,  with  the  instincts  of  hunger 
and  reproduction,  constitute  the  most  intense  metaphysical  con- 
ditions of  which  they  are  capable.  But  our  knowledge  of  this 
branch  of  the  subject  is  less  than  it  ought  to  be,  for  animals  pos- 
sess many  mental  attributes  for  which  they  get  little  credit. 

It  appears  to  be  impossible  to  account  for  the  highest  il lustra- 


214  GENERAL  EVOLUTION. 

tions  of  mimetic  analogy  in  any  other  way,  the  supposition  of 
Wallace  that  such  forms  must  be  spontaneously  produced,  and 
then  preserved  by  natural  selection,  being  no  explanation.  It  has 
been  shown  by  Bennett  that  the  chances  of  such  modification  aris- 
ing out  of  the  many  possibilities  are  exceedingly  small. 

If  the  above  positions  be  true,  we  have  here  also  the  theory  of 
the  development  of  intelligence  and  of  other  metaphysical  traits. 
In  accordance  with  it,  each  trait  appropriates  from  the  material 
world  the  means  of  perpetuating  its  exhibitions  by  constructing  its 
instruments.  These  react  by  furnishing  increased  means  of  exer- 
cise of  these  qualities,  which  have  thus  grown  to  their  full  expres- 
sion in  man. 


VI. 

A  EEVIEW   OF   THE   MODEEN  DOCTRmE    OF  EVO- 
LUTION.* 

The  doctrine  of  evolution  of  organic  types  is  sometimes  appro- 
priately called  the  doctrine  of  derivation,  and  its  supporters,  deriv- 
atists.  This  is  because  it  teaches  the  derivation  of  species,  genera, 
and  other  divisions,  from  pre-existent  ones,  by  a  process  of  modi- 
fication in  ordinary  descent  by  reproduction.  The  opposite  or 
creativist  doctrine  teaches  that  these  forms  were  created  as  we  see 
them  to-day,  or  nearly  so  ;  and  that  the  natural  divisions  and  spe- 
cies of  organic  beings  have  never  been  capable  of  change,  the  one 
into  the  other. 

I.    THE   EVIDENCE   FOR   EVOLUTIOIS^ 

The  reasons  w^hich  induce  me  to  accept  the  derivatist  doctrine, 
and  to  reject  the  creational,  fall  under  the  two  heads  of  probabil- 
ities and  conclusive  evidence.  The  probabilities  are  cumulative  in 
their  pointings,  and  strengthen  that  part  of  the  evidence  which 
is,  to  my  mind,  conclusive.  The  reasons  why  derivation  is  prob- 
able are  the  successional  relation  of  increment  or  decrement  of 
structure,  observed  in  : 

1.  Systematic  relation  (taxonomy)  ;  2.  Embryonic  growth 
(embryology)  ;  3.  In  geologic  time  (paleontology)  ;  4.  And  in  the 
coincidence  in  the  successions  seen  in  Nos.  1,  2,  and  3. 

The  fact  that  it  is  necessary  to  arrange  animals  in  an  order  cor- 
responding with  the  phases  of  their  embryonic  history  is  remark- 
able ;  but  the  further  fact,  shown  by  paleontology,  that  the  same 
succession  marked  the  ages  of  past  time,  at  once  brings  evolution 
within  the  limits  of  strong  probability.  Nevertheless,  all  this 
might  have  been  a  mere  system,  without  transitions  between  its 


*  Abstract  of  a  lecture  delivered  before  the  California  Academy  of  Sciences,  Oct. 
27,  1879. 


216  GENERAL  EVOLUTION. 

members ;  organic  types  miglit  have  been  created  unchangeable, 
but  presenting  the  mutual  relations  in  question.  But  if  transi- 
tions among  these  members  can  be  shown  to  take  i^lace,  then 
indeed  the  phenomena  mentioned  received  a  sufficient  explanation. 
They  are  seen  to  be  the  necessary  relations  of  the  parts  of  a  shift- 
ing scene  of  progression  and  retrogression  ;  they  express  combina- 
tions of  structure,  which,  though  often  long  enduring,  are,  never- 
theless, not  perpetual,  but  give  way  to  other  combinations  to  be 
in  their  turn  dissolved.  Now,  if  there  is  anything  well  known  in 
nature,  it  is  that  there  are  divisions  of  various  ranks  in  the  vege- 
table and  animal  kingdoms,  whose  contents  present  variations  of 
structure  which  are  confessedly  additions  to  or  subtractions  from 
the  characters  of  ancestors,  which  have  appeared  during  ordinary 
descent.  The  j^rotean  species,  genera,  etc.,  are  well  known  to 
biologists,  and  every  naturalist  who  admits  varieties,  sub-species, 
sub-genera,  etc.,  admits  derivation  so  far  as  they  are  concerned. 
The  facts  of  variation,  including  ''^sporting,"  etc.,  are  notorious, 
not  only  among  domesticated,  but  also  in  wild  animals  and  plants. 
The  facts  have  led  some  persons  to  suggest  that  species  have  been 
produced  by  evolution  from  a  single  specific  center,  but  that  the 
genus  and  other  comprehensive  divisions  are  unchangeable.  But 
I  think  I  have  shown,  in  a  paper  entitled  "  The  Origin  of  Gen- 
era," *  that  the  structural  characters  which  define  genera,  and  even 
higher  divisions,  are  subjects  of  variation  to  as  great  an  extent  as 
are  the  less  profound  specific  characters  ;  and,  moreover,  that  the 
evidence  of  derivation  which  they  present  is  singularly  clear  and 
conclusive.  The  changes  of  both  genus  and  species  character  are 
always  of  the  nature  of  additions  to  or  subtractions  from  those  of 
one  generation  displayed  by  their  descendants.  As  such,  they 
form  the  closing  chapters  of  the  embryonic  or  growth-history  of 
the  modified  generation. 

In  order  to  explain  more  fully  the  application  of  the  above 
statements,  I  introduce  a  few  examples  selected  from  the  subjects 
of  my  studies.  Their  number  might  be  indefinitely  extended.  I 
first  cite  the  genera  of  the  tailless  BatracMa  Anura  (frogs,  toads, 
etc.),  whose  relations  are  very  simple  and  clear,  and  show  the 
parallelism  between  adult  structure  and  embrj^onic  succession.  See 
above,  1  and  2. 

The  greater  number  of  BatracMa  Anura  fall  into  two  divis- 

*  Philadelphia,  1869.     "Proceedings  Academy  Natural  Sciences,  1868." 


REVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.     217 


Fig.  8. 


Fig.  9. 


ions,  which  differ  only  in  the  structure  of  the  lower  portion  of 
their  scapular  arch,  or  shoulder-girdle.     In  the  one  the  opposite 
halves  are  capable  of  movements  which  contract  or  expand  the 
capacity  of  the  thorax;   in  the  other  the  opposite  halves  abut 
against  each  other  so  as  to  be  incapable  of  movement,  thus  pre- 
serving the  size  of  the  thoracic  cavity.     But  during  the  early 
stages,  the  frogs  of  this  division  have  the  movable  shoulder-girdle 
which    characterizes     those    of    the 
other  division,  the  consolidation  con- 
stituting a  modification  superadded 
in    attaining    maturity.        Further- 
more,  young  Amir  a   are  toothless, 
and  one  section  of  the  species  with 
embryonic  shoulder-girdle  never  ac- 
quire   teeth.       So   here   we    have   a 
group   which    is    imperfect   in    two 
points  instead  of  one.     This  is  the 
tribe  Bufoniformia;   the  tribe  with 
teeth  and  embryonic  shoulder-girdle 
is    called    the    Arcifera,    and    that 
which  is  advanced  in  both  these  res- 
pects is  the  Raniformia.     Now  the 
frogs  of  each  of  these  divisions  pre- 
sent nearly  similar  scales  of  develop- 
ment of  another  part  of  the  skeleton, 
viz.,  the  bones  of  the  top  of  the  skull. 
We  find  some  in  which  one  of  these 
bones   (ethmoid)   is    represented    by 
cartilage  only,  and  the  frontoparietals 
and  nasals  are  represented  by  only  a 
narrow  strip  of  bone  each.     In  the 
next  type  the  ethmoid  is  ossified  ;  in 
the  next,  we  have  the  frontoparietal 
completely   ossified,    and   the   nasals 
range  from  narrow  strips  to  complete 
roofs ;    in  the  fourth  station  on  the 
line,  these  bones  are  rough,  with  a  hyperostosis  of  their  surfaces  ; 
and  in  the  next  set  of  species  this  ossification  fills  the  skin,  which 
is  thus  no  longer  separable  from  the  cranial  bones  ;  in  the  sixth 
form  the  ossification  is  extended   so  as  to  roof  in  the  temporal 
muscles  and  inclose  the  orbits  behind,  while  in  the  rare  seventh 


Fig.  10. 

SlIOULDEK-GIRDLES  OF  "  AnURA." 

Fig.  8,  of  the  Arciferous  type 
(Scaphiopus  holbroohi).  Fig.  9, 
Rana  temporaria^  tadpole  -nith 
budding  limbs.  Fig.  10,  do.  adult. 
Figs.  9  and  10  from  Parker. 


218  GENERAL  EVOLUTION. 

and  last  stage,  the  tympanum  is  also  inclosed  behind  by  bone. 
Now  all  of  these  types  are  not  found  in  all  of  the  families  of  the 
Anura,  but  the  greater  number  of  them  are.  Six  principal  fami- 
lies, four  of  which  belong  to  the  Arcifera,  are  named  in  the  dia- 
gram below,  and  three  or  four  others  might  have  been  added.  I 
do  not  give  the  names  of  the  genera  which  are  defined  as  above 
described,  referring  to  the  explanation  of  the  cuts  for  them,  but 
indicate  them  by  the  numbers  attached  in  the  plate,  which  corres- 
pond to  those  of  the  definitions  above  given.  A  zero  mark  signi- 
fies the  absence  or  non-discovery  of  a  generic  type. 


Sternum 

embryonic. 

Sternum  complete. 

Bufoniformia. 
Bufonidae. 

Arcifera. 

Eaniformia. 

Scaphiopidse 
and  Pelobatidae. 

Cystignathidse. 

Hylidae. 

Eanidae. 

1— 

1 

0 

1 

1 

0 

2— 

2 

2 

2 

2 

0 

3— 

3 

0 

3 

3 

3 

4— 

4 

4 

4 

4 

4 

5— 

5 

5 

0 

5 

5 

6— 

6 

6 

6 

6 

0 

1— 

7 

0 

0 

0 

0 

It  is  evident,  from  what  has  preceded,  that  a  perfecting  of  the 
shoulder-girdle  in  any  of  the  species  of  the  Bufoniform  and  Ar- 
ciferous  columns  would  place  it  in  the  series  of  Eaniformia.  An 
accession  of  teeth  in  a  species  of  the  division  Bufonifor?ma  would 
make  it  one  of  the  Arcifera  j  while  a  small  amount  of  change  in 
the  ossification  of  the  bones  of  the  skull  would  transfer  a  species 
from  one  to  another  of  the  generic  stations  represented  by  the 
numbers  of  the  columns  from  one  to  seven. 

There  are  few  groups  where  this  law  of  parallelism  is  so  readily 
observed  among  contemjoorary  types  as  the  Batracliia,  but  it  is 
none  the  less  universal.  The  kind  of  parallelism  usually  observed 
is  that  in  which  there  is  only  a  partial  resemblance  between  adults 
of  certain  animals  and  the  young  of  others.  This  has  been  termed 
*^  inexact  parallelism,"  and  the  relation  is  presented  by  forms  not 
very  nearly  phylogenetically  related.  The  more  remote  the  phylo- 
genetic  lines  of  two  types,  the  more  *"' inexact  "  will  their  parallel- 
ism be.  It  was  once  a  question  whether  any  parallelism  can  be 
traced  between  the  members  of  the  five  or  six  primary  divisions  of 
animals,  and  in  my  essay  on  the  *^  Origin  of  Genera,"  I  was  com- 
pelled to  state  that  there  was  then  ^'no  evidence  of  the  community 


KEVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.     219 


of  origin  of  these  diyisions."  Since  that  time,  Haeckel  has  pub- 
lished his  '^Gastraea  Theory."  This  is  a  grand  generalization 
from  the  facts  of  embryology,  which  shows  the  community  in 
type  of  the  early  stages  of  all  animals,  and  the  similarity  of  the 
phases  which  they  present  during  a  part  of  their  larval  life.  The 
exceptions  to  this  law  which  have  been 
observed  will  probably  be  explained,  as 
have  been  those  which  have  been  urged 
against  the  law  of  homologies  in  anatomy. 
The  paleontology  of  the  Batracliia 
anura  is  largely  unknown,  so  we  must 
look  elsewhere  for  proof  of  the  truth  of 
the  fourth  proposition,  viz.,  that  the  suc- 
cessional  relation  in  embryology  corre- 
sponds with  that  shown  by  paleontology 
to  have  existed  in  geologic  time. 

For  this  purpose  I  select  one  of  the 
most  complete  series 
known  to  paleontology; 
that  of  the  camels  or 
CameUdcB,  whose  re- 
mains are  found  abund- 
antly in  various  parts 
of  our  country.  The 
succession  of  the  known 
genera  is  seen  in  the 
structure  of  the  bones 
of  the  feet,  and  of  the 
superior  incisor  and 
premolar  teeth.  The 
metatarsal  and  meta- 
carpal bones  are  or  are 
not  co-ossified  into  a 
cannon  bone  ;  the  first 
and  second  superior  in- 
cisor teeth  are  present, 
rudimental  or  wanting, 
and  the  premolars  num- 
ber from  four  to  one. 
The  relations  which 
these   conditions   bear 


Fig.  11. 


Fig.  12. 


Fig.  W.—Poebrotherium  vilsoni  carpus  and  meta- 
carpus with  end  of  radius,  three  fifths  natural  size. 
Original ;  from  White  Eiver  Miocene  of  Colorado. 

Fig.  12.— Carpus  and  metacarpus  of  Procamelus 
occidentalism  about  two  fifths  natural  size.  Original ; 
from  report  of  G.  M.  Wheeler,  U.  S.  Expl.  Surv.  W.  ot 
100th  Mer.,  vol.  iv,  pt.  ii.     From  New  Mexico. 


PLATE  IV. 


Fig.  1. 


Fio.  33. 


Fig.  2. 


Fig.  3,  wanting. 


FjG.  5. 


Fig.  6. 


Fig.  6. 


Fig.  7. 
BUFONID^. 


Fig.  7,  wanting. 
SCAPHIOPIDJE  AND  PELOBATIDM. 


PLATE   V. 


Fig.  1. 


Fig.  1. 


Fig.  2. 


Fig.  2. 


Fig.  3. 


Fig.  83. 


Fig.  32. 


Fig.  3  1. 


Fig.  3. 


Fig.  31. 


Fig.  32. 


Fig.  4. 


Fig.  33. 


Fig.  6. 


Fig.  6. 
CYSTIGNATHID^. 


Fig.  5. 
RANID^. 


222  GENEKAL  EVOLUTION. 

EXPLANATION   OF   CUTS   OF   CRANIA  OF  ANURA. 

The  numbers  in  each  column  correspond  with  the  types  of  ossification  mentioned 
in  the  text,  and  are  the  same  as  those  in  the  table  of  families  given  in  the  same  con- 
nection. The  power  numbers  attached  to  Fig.  3,  represent  the  degree  of  ossification 
of  the  nasal  bones,  except  the  ~\  which  signifies  unossified  ethmoid.  Most  of  the 
cuts  are  original. 

BcFONiDJE. — Fig.  2,  anterior  part  of  skull  of  Chdydohairachas  gouldi  Gray,  from 
Australia.  Fig.  3,  do.  of  Schismaderma  carens  Smith,  S.  Afi"ica.  Fig.  6,  top 
of  head  of  Peltaphryne  peltacephala  D.  and  B.,  Cuba.  Fig.  7,  top  of  head  of 
Otaspis  empusa  Cope,  Cuba. 

SoAPHiopiD^  AND  Pelobatid^. — Fig.  2,  diagram  of  top  of  cranium  of  Didocus 
ccdcaratus  Micahelles,  Spain.  Fig.  5,  skull  of  Scaphiopm  liolhroolci  Harl., 
United  States.  Fig.  6,  skull  of  Cultripes  provincialis,  from  France,  after 
Duges. 

llYLiDiE. — Fig.  1,  Thoropa  miliaris  Spix.,  Brazil.  Fig.  2,  Hupsiboas  doumerci  D. 
and  B.,  Surinam.  Fig.  2\  Hypaihoas  punctatus  Schn.,  Brazil.  Fig.  3^,  Scytopis 
vemdosus  Daudin,  Brazil.  Fig.  6,  Trachycephalus  geographicus  D.  and  B., 
Brazil,  after  Steindachner. 

Cystignathid^. — Fig.  1,  Eusophus  nehuloaiis  Gir.,  Chili.  Fig.  2,  Borhoroccetes  tas- 
maniensis  Gthr.,  Tasmania.  Fig.  3,  Elosia  nasiis  Licht.,  Brazil.  Fig.  3^,  Ify- 
lodes  oxyrhyiichus  D.  and  B.,  W.  Indies.  Fig.  4,  Grypiscus  umbrinus  Cope, 
Brazil.     Fig.  6,  Calyptocephalus  gayi  D.  and  B.,  Chili. 

Ranid^. — Fig.  3~^ — Ranula  chry&oprasina  Cope,  Costa  Rica.  Fig.  3,  Rana  oxy- 
rhyncha  Sund.,  S.  Africa.  Fig.  3\  Rana  clamata  Daud.,  N.  America.  Fig.  3^, 
Rana  agilis  Thomas.  Fig.  3'^,  Rana  hexadactyla  Less.,  India.  Fig.  4,  PoJy- 
pedates  quadrilineatus  D.  and  B.,  Ceylon. 

to  geologic  time  are  displayed  in  the  follo^^ng  table,  commencing 
with  the  lowest  horizon : 

No  cannon  bono.  Cannon  bone  present. 


Incisor  teeth  present.     Incisors  one  and  two  wanting 


4  premolars,         3  prem'rs.    2  prem's.  1  prem'r. 


r- 


Lower  Miocene.  -]  Pochrotherium. 

{  Protolahis. 

Upper  Miocene.  <  Procamelus 


Pliocene  and  Recent. 


(  Pliauchenia. 

Camelus. 


Auchenia. 


This  table  shows  that  geological  time  has  witnessed,  in  the  his- 
tory of  the  CamelidcB,  the  consolidation  of  the  bones  of  the  feet 
and  a  great  reduction  in  the  numbers  of  the  incisor  and  premolar 
teeth.     The  embryonic  history  of  these  parts  is  as  follows  :  In  the 


REVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.     223 

foetal  state  all  the  Ruminantia  (to  which  the  camels  belong)  have 
the  cannon  bones  divided  as  in  Poehr other ium  ;  they  exhibit  also 
incisor  teeth,  as  in  that  genus  and  Protolabis.    Very  young  recent 


Fig.  13. — Protolabis  Iransmontanus  Cope,  skull,  a,  in  profile ;  5,  from  below,  one 
third  (linear)  natural  size.  Original;  from  vol.  iv,  Report  U.  S.  Geol.  Surv.,  under 
F.  V.  Hayden.     Ticholeptus  bed  of  Oregon. 

camels  have  the  additional  premolar  of  Pliauchenia.  They  shed 
this  tooth  at  an  early  period,  but  very  rarely  a  camel  is  found 
in  which  the  tooth  persists.     The  anterior  premolar  of  the  normal 


Fig.  14. — Procamelus  occidentalis  Leidy,  profile  of  skull,  about  two  sevenths  natu- 
ral size.  Original ;  from  report  of  Capt.  G.  M.  Wheeler,  IT.  S.  Geol.  Geog.  Surv.  W. 
of  100th  Mer.     Vol.  iv,  pt.  ii.     From  Loup  Fork  bed  of  New  Mexico. 

Camelus  is  in  like  manner  found  in  the  young  lama  (Auchenia), 
but  is  shed  long  before  the  animal  attains  maturity.  I  may  add 
that  in  some  species  of  Procmnelus  caducous  scales  of  enamel 


224:  GENERAL  EVOLUTIOIN". 

and  dentine  in  shallow  cavities  represent  the  incisive  dentition  of 
Protolabis. 

It  remains  to  show  that  characters  of  the  kind  above  men- 
tioned are  sometimes  inconstant ;  that  they  may  or  may  not  ap- 
pear in  individuals  of  a  species.  Under  such  circumstances  it  is 
evident  that  their  origin  does  not  imply  any  break  in  the  line  of 
descent. 

First,  as  to  a  family  character.  It  is  well  known  that  the  deer 
differ  from  the  giraffes  in  the  presence  of  a  burr  or  ring  of  osseous 
excrescences  surrounding  the  base  of  the  horn.  Now,  in  the  ex- 
tinct tertiary  genus  Cosoryx  there  are  three  species  which  possess 
or  lack  this  burr  indifferently.  Why  some  individuals  should, 
and  others  should  not  possess  it,  is  not  known.* 

Second,  as  to  a  generic  character.  The  genus  Canis  (dog)  is 
defined  by  the  presence  of  two  tubercular  molars  in  the  inferior 
series.  The  allied  genus  Tlious  possesses  three  such  teeth,  while 
Idicyon  has  but  one.  Kow  examples  of  Canis  familiar  is  (domes- 
tic dog)  with  but  one  tubercular  molar  are  not  rare,  while  an  in- 
dividual with  three  is  occasionally  found. 

To  take  another  case.  The  normal  dentition  of  Homo  (man) 
is,  on  each  side,  incisors,  2  ;  canine,  1  ;  premolars,  2  ;  molars,  3. 
It  is  very  common  to  find  in  the  higher  races,  individuals  who 
have  molars  only  two  in  one  or  both  jaws  ;  and  the  absence  of 
the  external  incisors  of  the  upper  jaw  is  almost  as  frequently  met 
with.  Here  we  have  two  new  generic  variations  in  one  and  the 
same  species. 

In  specific  characters  variations  are  most  familiar.  Thus,  the 
young  of  deer  are  generally  spotted,  and  the  adults  are  nearly 
uniform  in  coloration.  Some  deer  (as  the  Axis)  retain  the  spotted 
coloration  throughout  life,  while  an  occasional  spotted  individual 
of  unicolor  species  is  a  violation  of  specific  character  by  a  failure 
to  develop.  The  larvae  of  some  salamanders  are  of  uniform  col- 
oration, and  the  adults  spotted.  The  unicolor  adults  of  the  same 
species,  not  uncommonly  met  with,  present  examples  of  the  same 
kind  of  variation. 

Any  biologist  can  select  hundreds  of  similar  cases  from  his 
special  department  of  study. 

*  The  explanation  I  have  offered  is  that  the  horn  was  stripped  of  its  integuments 
to  the  position  of  the  burr  by  the  animals  in  fighting.  The  condition  of  the  speci- 
mens renders  this  hypothesis  pi'obable.  See  "Report  U.  S.  Expl.  Surv.  W.  100th 
Mer.,"  Capt.  G.  M.  Wheeler,  vol.  iv,  pt.  ii. 


EEYIEW  OF  THE  MODERN  DOCTRmE  OF  EYOLUTIOIT.    225 


II.    THE   LAWS   OF   EVOLUTIOIT. 

Having  reviewed  the  reasons  why  the  doctrine  of  evolution 
should  be  received  as  truth,  I  desire  to  give  attention  to  the  laws 
which  may  be  made  out  by  reference  to  its  phenomena.  Progress 
in  this  direction  is  difficult,  owing  to  the  natural  impediments  in 
the  way  of  studying  the  history  of  the  growth  of  living  beings. 
We  will,  however,  commence  by  examining  more  fully  the  phe- 
nomena with  which  we  have  to  deal. 

It  is  well  understood  that  the  world  of  animal  life  is  a  nicely 
adjusted  equilibrium,  maintained  between  each  individual  and  its 
environment.  This  environment  exerts  forces  both  purely  physi- 
cal, and  those  exercised  by  other  animals.  Animals  antagonize 
each  other  in  procuring  food,  whether  that  food  consist  of  vegeta- 
tion or  of  other  animals,  but  in  the  latter  case  the  conflict  is  more 
severe.  A  similar  competition  exists  among  male  animals  in  the 
matter  of  reproduction.  These  exhibitions  of  energy  constitute 
the  struggle  for  existence,  which  is  the  daily  business  of  the  living 
world.  It  is  well  understood  that  in  this  struggle  the  individuals 
best  provided  with  means  of  self-preservation  necessarily  survive, 
while  the  weak  in  resources  must  disappear  from  the  scene. 
Hence  those  which  survive  must  display  some  especial  fitness  for 
existence  under  the  circumstances  of  their  environment,  whatever 
they  may  be.  So  the  ^^ survival  of  the  fittest"  is  believed  to  be  a 
law  of  evolution,  and  the  process  by  which  it  is  brought  about  has 
been  termed  ** natural  selection."  The  works  of  Darwin  and 
others  have  satisfied  biologists  that  this  is  a  vera  causa. 

Before  the  excellence  of  a  machine  can  be  tested,  it  must  exist, 
and  before  man  or  nature  selects  the  best,  there  must  be  at  least 
two  to  choose  from  as  alternatives.  Furthermore,  it  is  exceedingly 
improbable  that  the  nicely  adapted  machinery  of  animals  should 
have  come  into  existence  without  the  operation  of  causes  leading 
directly  to  that  end.  The  doctrines  of  **^ selection  "  and  "sur- 
vival "  plainly  do  not  reach  the  kernel  of  evolution,  which  is,  as  I 
have  long  since  pointed  out,  the  question  of  "the  origin  of  the 
fittest."  The  omission  of  this  problem  from  the  discussion  of 
evolution,  is  to  leave  Hamlet  out  of  the  play  to  which  he  has 
given  the  name.  The  law  by  which  structures  originate  is  one 
thing  ;  those  by  which  they  are  restricted,  directed,  or  destroyed, 
is  another  thing. 

There  are  two  kinds  of  evolution,  progressive  and  retrogres- 
15 


226  GENERAL  EVOLUTION. 

sive  ;  or,  to  use  expressions  more  free  from  objection,  by  addition 
of  parts,  and  by  subtraction  of  parts.  It  is  further  evident  that 
that  animal  which  adds  something  to  its  structure  which  its  par- 
ents did  not  possess,  has  grown  more  than  they ;  while  that 
which  does  not  attain  to  all  the  characteristics  of  its  ancestors  has 
grown  less  than  they.  To  express  the  change  in  the  growth-his- 
tory which  constitutes  the  beginning  of  evolution,  I  have  employed 
the  terms  *^ acceleration  and  retardation."  Generally  these  ex- 
pressions are  literally  exact,  i.  e.,  there  is  an  increased  rate  of 
growth  in  evolution  by  addition,  and  a  decreased  rate  in  evolution 
by  subtraction  ;  but  this  is  not  always  the  case,  for  some  divisions 
of  animals  have  increased  the  length  of  their  growth-period  with- 
out reference  to  evolution  in  structure.  The  terms  express  the 
phenomena  figuratively,  where  not  exact  in  the  sense  of  time,  and 
I  believe  they  are  sufficiently  clear.  The  origin  of  the  fittest  is 
then  a  result  of  either  acceleration  or  retardation.  It  is  easy  to 
perceive  that  a  character  which  makes  its  appearance  in  a  j^arent 
before  or  near  to  the  breedino^  season  is  likelv  to  be  transmitted  to 
its  descendants  ;  so  also  a  character  which  is  lost  near  this  time  is 
likely  to  be  wanting  from  the  offspring.  The  causes  of  accelera- 
tion and  retardation  may  next  claim  attention. 

It  is  well  known  that  the  decomposition  of  the  nutritive  fluids 
within  living  animals  gives  rise,  in  the  appropriate  tissues,  to 
exhibitions  of  different  kinds  of  forces.  These  are,  motion  in  all 
classes  ;  heat  in  some  only ;  in  a  still  smaller  number,  electricity 
and  light ;  in  all.  at  certain  times,  growth-force  or  bathmism  ;  in 
many,  phrenism  or  mental  or  thought-force.  These  are  all  derived 
from  equivalent  amounts  of  chemical  force  which  are  liberated  by 
the  dissolution  of  protoplasm.  This  organic  substance,  consisting 
of  CHON,  undergoes  retrograde  metamorphosis,  being  resolyed 
into  the  simpler  CDs,  HO,  etc.,  and  necessarily  liberates  force  in 
the  process.  None  of  the  functions  of  animal  life  can  be  main- 
tained without  supplies  of  protoplasm.  TVe  have  here  to  do  with 
bathmism.  It  consists  of  the  movement  of  material  to,  and  its 
deposition  in,  certain  definite  portions  of  the  growing  egg,  or 
foetus,  as  the  case  may  be.  It  is  different  in  its  movements  in 
every  species,  and  its  direction  is  probably  the  resultant  of  a  num- 
ber of  opposing  strains.  In  the  simplest  animals  its  polar  equili- 
brium is  little  disturbed,  for  these  creatures  consist  of  nearly 
globular  masses  of  cells.  As  we  ascend  the  scale  a  greater  and 
more  marked  interference   becomes   apparent ;  radiated  animals 


REVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.    227 

display  energy  in  a  number  of  radiating  lines  rather  than  in  the 
spaces  between  them  ;  and  in  longitudinal  animals,  a  longitudinal 
axis  exceeds  all  others  in  extent  and  importance.  In  the  highest 
animals  its  results  are  much  more  evident  at  one  extremity  of  the 
axis  (head)  than  at  the  other,  and  the  diyerging  lines  are  reduced 
to  four  (the  limbs).  In  each  species  the  movements  of  this  force 
are  uniform  and  habitual,  and  it  is  evident  that  the  habit  is  so 
deeply  seated  that  only  a  very  strong  dynamic  interference  can 
modify  or  divert  it.  The  interfering  forces  are  probably  all  those 
transmissible  through  living  tissue,  and  especially  molar  force. 
Thus  every  species  has  its  own  specific  kind  of  bathmic  force. 

The  characters  of  living  beings  are  either  adaptive  or  non- 
adaptive  ;  they  are  either  machines  especially  fitted  to  meet  the 
peculiarities  of  their  environment,  or  they  are  not.  Among  the 
latter  may  be  ranged  rudimental  structures  and  also  many  others 
of  no  sufficient  use.  They  are  all  due  either  to  excess  or  defect  of 
growth-force  ;  they  are  either  consequences  of  a  removal  of  nutri- 
tive material  to  other  portions  of  the  body ;  or  they  are  due  to  an 
excess  of  such  material  which  renders  an  organ  or  part  useless 
through  disproportionate  size.  Of  the  former  class  may  be  cited 
the  absence  of  the  tail  in  some  monkeys  and  birds  ;  also  of  the 
teeth  in  some  Cetaceans  ;  of  the  latter  kind  are  the  enormous 
tusks  of  the  mammoth  and  the  recurved  superior  canines  of  the 
bab}Tussa.  The  change  of  destination  of  this  material  has  been 
probably  due  to  the  construction  of  adaptive  machines  whose  per- 
fection from  time  to  time  has  required  the  use  of  larger  and  larger 
proportions  of  force  and  material. 

In  considering  the  origin  of  adaptive  structures,  two  alterna- 
tive propositions  are  presented  to  us.  Did  the  occasion  for  its  use 
follow  the  appearance  of  the  structure,  or  did  the  need  for  the 
structure  precede  its  appearance  ?  The  following  answer  to  the 
question  has  always  been  the  most  intelligible  to  me.  Animals 
and  plants  are  dependent  for  existence  on  their  environment.  It 
is  an  every-day  experience  that  changes  in  environment  occur 
without  any  preparation  for  them  on  the  part  of  living  things.  If 
the  changes  are  very  great,  death  is  the  result.  It  is  evident  that 
the  influence  of  environment  is  brought  to  bear  on  life  as  it  is,  or 
has  been,  and  that  special  adaptations  to  it  on  their  part  must  fol- 
low, not  precede,  changes  of  climate,  topography,  population,  etc. 
We  have  another  important  consideration  to  add  to  this  one,  viz., 
the  well-known  influence  of  use,  i.  e.,  motion,  on  nutrition.     Ex- 


228  GENERAL  EVOLUTION. 

ercise  of  an  organ  determines  nutritive  material  to  it,  and  the 
nervous  or  other  influence  which  does  this,  equally  determines 
nutritive  material  to  localities  in  the  body  to  which  an  effort  to 
move  is  directed,  whether  an  executive  organ  exist  there  or  not. 
The  habit  of  effort  or  use  determining  the  nutritive  habit  must  be 
inherited,  and  result  in  the  growing  young,  in  additional  struct- 
ure. Change  of  structure,  denied  to  the  adult  on  account  of  its 
fixity,  will  be  realized  in  the  growing  or  plastic  condition  of  foetal 
or  infant  life.  The  two  considerations  here  brought  forward  lead 
me  to  think  that  the  cause  of  acceleration,  in  many  adaptive 
structures,  is  environment  alone,  or  environment  producing  move- 
ments, which  in  turn  modify  structure.  The  character  of  the 
stimulus  in  the  successive  grades  of  life  may  be  expressed  by  the 
following  table,  passing  from  the  lowest  to  the  highest : 

1.  Passive  or  motionless  beings  : 

by  climate  and  food  only. 

2.  Movable  beings  : 

by  climate,  food  and  motion. 
By  motion  either  : 
a,  unconscious,  or  * 
aa,  conscious,  which  is, 

h,  reflex,  or 
M,  directed  by  desire  without  ratiocination,  or 
Mb,  by  desire  directed  by  reason. 

The  only  general  rules  as  to  the  direct  influence  of  motion  on 
structure  which  can  be  laid  down  at  present  are  two,  viz.,  That 
density  of  tissue  is  in  direct  ratio  to  pressure,  up  to  a  certain 
point ;  t  and  that  excess  of  growth-force,  in  a  limited  space,  pro- 
duces complications  of  the  surfaces  stimulated.  \  These  and  other 
laws,  yet  unknown,  have  probably  led  the  changes  expressed  by 
evolution,  while  many  others  have  followed  the  disturbance  of 
equilibrium  which  they  have  produced. 

I  here  allude  incidentally  to  the  question  of  transmission  or 
inheritance.  It  has  been  maintained  above  that  the  bathmic  force 
of  each  species  is  different  from  that  of  all  other  sj^ecies.  This 
force  is  characteristic  of  some  unit  of  organization  of  living  be- 

*  Movements  coming  under  this  head  are  often  called  reflex, 
•f-  See  "Penn.  Monthly,"  1872;  this  work  Art.  L 
X  "  Method  of  Creation,"  Philadelphia,  1871. 


EEVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.    229 

ings  ;  and  this  probably  consists  of  several  molecules.  This  unit 
has  been  termed,  by  Haeckel,  the  plastidule.  The  transmission 
of  the  bathmic  force  of  one  generation  to  another  would  be  effected 
by  the  transmission  of  one  or  more  living  plastidules  ;  and  this  is 
probably  precisely  what  is  accomplished  in  reproduction.  The 
Dynamic  Tlieory  of  reproduction  I  proposed  in  1871,*  and  it  has 
been  since  adopted  by  Haeckel  under  the  name  of  perigenesis.  I 
compared  the  transmission  of  bathmic  force  to  that  of  the  phe- 
nomenon of  combustion,  which  is  a  force  conversion  transmitted 
from  substance  to  substance  by  contact.  The  recent  observations 
of  Hertwig,  Biitschli  and  others,  confirm  this  view.  The  theory 
of  pangenesis,  devised  to  explain  the  phenomenon  of  rej^roduction, 
is  to  my  mind  quite  inadequate. 

III.    METAPHYSICS   OF   EVOLUTION". 

I  enter  here  upon  a  wide  field,  over  which  I  can  only  skim  on 
an  occasion  like  the  present.  The  subject  has  been  already  intro- 
duced by  reference  to  consciousness  as  modifying  movement ;  of 
course,  then,  if  movement  modify  structure,  the  latter  is  influenced 
by  consciousness.  The  word  consciousness  was  then,  and  is  now, 
used  in  its  simplest  sense,  viz. :  as  synonymous  with  physical 
sensibility.  Its  lowest  and  most  usual  exhibition  is  the  sense 
of  touch  ;  the  special  senses,  taste,  sight,  etc.,  are  higher  forms, 
while  thoughts  and  desires  are  organized  products  of  the  same  raw 
material.  Consciousness  can  not  be  denied  to  many  of  the  inferior 
animals  ;  indeed,  if  we  grant  it  to  any,  we  must  admit  that  it  is 
displayed  at  times  by  even  the  lowest  Protozoon.  That  these 
humble  creatures  should  possess  it,  is  apparently  quite  as  proba- 
ble as  that  the  very  similar  bioplasts  of  the  brain  of  man  should 
be  its  seat. 

Consciousness  alone  is  not  a  sufficient  basis  for  the  develop- 
ment of  mind.  For  this,  one  more  element  is  necessary,  and  that 
is,  memory.  Impressions  made  by  the  environment  are  registered, 
and  soon  cease  to  be  present  in  consciousness.  Under  the  influ- 
ence of  association  the  impressions  return  to  consciousness.  Asso- 
ciations are  those  of  place,  of  the  order  of  time,  and  of  similarity 
or  difference  in  various  qualities,  as  size,  color,  or  any  other  physi- 
cal features.  Experiences  of  these  qualities  are  to  all  conscious 
beings  either  painful,  indifferent,  or  pleasurable.     When  associa- 

*  "Method  of  Creation,"  18V1. 


230  GENERAL  EVOLUTION. 

tion  requires,  events,  objects,  or  cliaracteristics,  are  returned  to 
consciousness  in  the  order  in  which  they  cohere  most  firmly  in 
the  mind,  which  may  or  may  not  be  that  in  which  they  entered  it. 
The  liking  for  or  dislike  to  the  object,  are  equivalent  to  an  attrac- 
tion to  or  repulsion  from  it.  Thus  experience  is  begotten  :  as  its 
material  increases,  new  combinations  are  formed,  new  relations 
observed,  and  in  the  highest  tyipes  of  mind,  laws  are  discovered. 
No  one  can  deny  memory  to  animals  ;  it  is  the  medium  of  their 
education  by  man,  and  has  been  as  well  the  means  of  their  edu- 
cation by  nature.  Impressions  cause  a  re-arrangement  of  cer- 
tain elements  of  structure  which  give  the  form  to  consciousness 
when  it  arises  again.  It  is  also  probable  that  these  arrangements 
are  not  the  same  as  those  which  represent  classifications  and  con- 
clusions, but  that  nevertheless  the  arrangement  or  organization 
of  these  is  determined  by  the  simpler  arrangements  caused  by 
perceptive  stimuli.  Experience  produces  these  combinations  in 
the  bioplastic  aggregations  of  all  animals,  be  they  in  the  form  of 
ganglia,  brains,  or  less  specialized  forms.  Nowhere  in  the  human 
organism  are  the  effects  of  effort  and  use  so  strikingly  witnessed 
as  in  the  increase  of  brain  power  ;  and  familiarity  with  the  educa- 
tion of  the  lower  animals  shows  that  this  is  the  case  with  them 
also,  though  in  a  lesser  degree  than  in  man. 

If,  then,  we  grant  the  p^ropositions,  first,  that  effort  and  use 
modify  structure  ;  and  second,  that  effort  and  use  are  determined 
by  mind  in  direct  ratio  to  its  development,  we  are  led  to  the  con- 
clusion that  evolution  is  an  outgrowth  of  mind,  and  that  mind  is 
the  parent  of  the  forms  of  living  nature.  This  is,  however,  to 
reverse  a  very  usual  evolutionary  hypothesis,  viz. :  that  mind  is 
the  product  and  highest  development  of  the  universe  of  matter 
and  force.  The  contradiction  is,  however,  not  so  absolute  as  at 
first  appears.  By  mind,  as  the  author  of  the  organic  world,  I 
mean  only  the  two  elements,  consciousness  and  memory.  But  it 
is  the  view  of  some  thinkers  that  consciousness  is  a  product ;  that 
it  is  not  only  a  correlative  of  force,  but  a  kind  of  force.  To  the 
latter  theory  I  can  not  subscribe ;  when  it  becomes  possible  to 
metamorphose  music  into  potatoes,  mathematics  into  mountains, 
and  natural  history  into  brown  paper,  then  we  can  identify 
consciousness  with  force.  The  nature  of  consciousness  is  such 
as  to  distinguish  it  from  all  other  thinkable  things,  and  it 
must  be  ranged  with  matter  and  force  as  the  third  element  of  the 
universe. 


EEVIEW  OF  THE  MODERN"  DOCTRINE  OF  EVOLUTION.     231 

It  is  true  that  unconsciousness  does  not  imply  absence  of  life 
as  generally  understood.  A  majority  of  the  processes  of  life  are 
performed  unconsciously  by  living  creatures  ;  mind  itself  being 
no  exception  to  this  rule.  There  is  another  class  of  acts  whose 
performance  produces  sensation,  but  consciousness  is  not  con- 
cerned in.  them  as  an  immediate  cause.  Therefore,  it  is  a  com- 
mon endeavor  to  associate  reflex  and  unconscious  acts  with  the 
molecular  movements  of  inorganic  and  non-living  substances. 
But  the  one  great  difficulty  in  making  this  identification  has 
never  been  surmounted.  This  is  the  different  nature  of  the 
movements  in  the  two  cases.  In  non-living  matter  they  are  sim- 
ply polar,  nothing  more.  In  living  beings  they  display  design. 
Perhaps  I  use  the  word  *^  design  "  in  a  new  sense,  but  the  expres- 
sion is  nevertheless  appropriate.  What  I  mean  is,  that  the  move- 
ments of  living  things  have  direct  reference  to  consciousness,  to 
the  satisfaction  of  pleasures,  and  to  the  avoidance  of  pains.  The 
molecular  movements  within  animals  of  the  simplest  class  are  the 
digestion  of  food  and  the  elaboration  of  the  materials  of  repro- 
duction. The  molar  movements  of  the  simplest  animals  are  to 
enable  them  to  escape  the  pains  of  hunger  and  celibacy.  More- 
over there  is  reason  why  the  movements  of  living  beings  display 
design.  We  all  know  the  nature  of  habits ;  how  they  are  per- 
formed unconsciously,  and  as  automatically  as  digestion  itself. 
But  did  any  one  ever  know  of  a  habit  in  an  animal,  whose  origin 
he  could  trace,  which  has  been  formed  in  unconsciousness  ?  Ac- 
cording to  our  knowledge,  habits  are  always  the  result  of  stimuli 
which  are  consciously  felt,  and  which  cause  by  repetition  or 
through  reminiscence  a  repetition  of  the  resulting  movement. 
After  a  sufficient  number  of  rej^etitions  such  an  act  becomes  a 
habit,  i.  e.,  is  performed  automatically,  or  without  the  interven- 
tion of  effort,  and  frequently  without  consciousness.  It  thus  be- 
comes a  part  of  the  character  of  the  individual  or  species.  This 
common  phenomenon  is  explained  by  the  hypothesis  that  an  or- 
ganization of  the  centers  controlling  action  is  caused  by  the  efforts 
of  the  animal  under  the  stimulus,  and  that  finally  a  machine  is 
constructed  which  determines  the  nature  of  the  force  expended, 
without  further  mental  exertion  of  the  individual.  Such  a  pro- 
cess is  education,  and  the  result  is  an  addition  to  the  stock  of 
faculties  already  on  hand.  Thus  is  explained  the  vast  number  of 
automatic  and  unconscious  activities  displayed  by  animals  ;  to  the 
same  source,  I  believe,  the  common  reflex  acts  may  be  traced ;  it 


232  GENERAL  EVOLUTION. 

even  appears  to  me  probable  that  the  organic  functions  in  general 
have  had  the  same  origin.*  While  these  latter  have  mostly  long 
since  passed  beyond  the  control  of  the  mind,  portions  of  the  uro- 
genital functions  still  linger  within  the  confines  of  its  jurisdiction. 
Thus  have  consciousness  and  mind  endowed  living  nature  with 
useful  functions ;  and  this,  which  may  be  called  the  Theory  of 
Endoiument,  accounts  for  the  element  of  design  which  is  so  puz- 
zling when  seen  in  unconscious  and  reflex  acts. 

As  it  has  been  maintained  above,  that  structure  is  the  effect  of 
the  control  over  matter  exercised  by  mind,  it  is  evident  that  the 
evolution  of  mind  must  be  directly  followed  by  corresponding  de- 
velopment of  organism.  The  science  of  paleontology  substantiates 
this  theory  in  a  wonderful  manner.  But  the  animal  mind  being 
generally  occupied  with  simple  functions,  its  expressions  in  struct- 
ure are  usually  nothing  more  than  the  progressive  creation  of  im- 
proved instruments  for  obtaining  food,  resisting  climate,  escaping 
enemies,  and  reproducing  their  kind.  The  struggles  of  animals 
have  been  seen  on  this  j^latform,  and  mind  has  only  been  necessary 
to  aid  in  accomplishing  the  ends  above  mentioned.  AYonderfully 
effective  machines  for  grinding,  cutting,  seizing,  and  digging  ;  for 
running,  swimming,  and  flying  have  been  produced.  The  develop- 
ment of  mind  proper  must  appear  in  the  size  and  structure  of  the 
brain  ;  and  though  the  history  of  the  latter  in  past  ages  must 
always  remain,  in  large  part,  hidden  from  us,  it  is  known  that  in 
the  former  respect  there  has  been  great  progress  made  in  various 
lines  of  animals.  Now  the  line  which  has  carried  brain  to  its  pres- 
ent development  in  man,  the  Quadrumana,  has  been  deficient  in 
special  mechanical  excellencies  of  the  kind  enumerated  above. 
Perhaps  primitive  inferiority  in  these  many  respects  has  kept  the 
Quadrumana  under  greater  mental  tension,  and  compelled  them 
to  exercise  caution  in  their  acts,  and  give  that  opportunity  to 
thought  which  was  less  demanded  in  the  case  of  other  animals. 
Furthermore,  if  they  are  less  specialized  in  their  mechanism  than 
most  other  Mammalia,  they  are  less  restricted  by  it  to  peculiar 
modes  of  life.  They  are  more  versatile,  and  more  capable  of  the 
adoption  of  new  habits  as  a  consequence.  And  here  we  have  a 
glimpse  of  a  most  important  principle  in  evolution,  which  is  the 
keynote  to  its  method  ;  this  is  what  I  have  called  the  The  Doctrine 
of  the  Unspecialized. 

*  "  Consciousness  in  Evolution."     "  Penn  Monthly,"  1875. 


REVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.    233 

Paleontology  shows  that  the  succession  of  living  types  has  not 
been  in  a.  single  straight  line.  It  has  been  in  many  divergent  lines, 
and  a  large  number  of  them  have  not  continued  to  the  present 
time.  The  history  of  life  has  been  well  compared  to  a  tree  with 
divergent  branches,  many  of  which  do  not  reach  the  elevation  of 
the  summit.  Furthermore,  in  the  many  cases  in  which  we  can 
trace  the  lower  lines  to  the  present  period,  it  is  evident -that  in 
-  their  present  condition  they  could  not  have  given  rise  to  the  higher 
forms.  Each  line,  in  fact,  has  developed  to  an  extreme  of  spe- 
cialization of  structure,  which  it  would  seem  is  incapable  of  modifi- 
cation in  any  direction  very  divergent  from  that  which  it  has  al- 
ready taken.  Much  less  have  such  specialized  types  been  able  to 
survive  the  environment  for  which  they  were  designed  ;  with  im- 
portant changes  in  that  respect  they  have  perished.  A  few  exam- 
ples will  serve  to  illustrate  my  meaning.  The  direction  of  develop- 
ment has  been  from  fishes,  through  BatracMa  and  rei)tiles,  to  birds 
and  mammals.  But  we  can  not  derive  any  living  type  from  the 
osseous  fishes  of  the  present  or  past  ages  {Teleostomi):  to  find  the 
origin  of  BatracMa,  we  must  pass  below  these  to  more  generalized 
and  older  forms,  the  Dipnoi,  a  class  whose  position  in  the  system 
was  for  years  a  controverted  point.  We  can  not  obtain  Mammalia 
from  any  of  the  existing  types  of  reptiles,  but  we  must  go  back  to 
the  Permian  period,  and  trace  their  outlines  in  the  Tlieromorplia 
of  that  day.  In  spite  of  the  prophetic  resemblance  of  these 
remarkable  animals,  they  are  inferior  to  later  Eeptilia  in  the 
structure  of  their  vertebral  column,  and  display  resemblance  to 
some  of  their  immature  stages,  as  well  as  to  those  of  the  Mammalia. 
Among  mammals  we  can  not  derive  monkeys  from  Carnivora  or 
Ungulata,  nor  the  latter  from  each  other,  but  can  only  trace  their 
close  approximation  in  the  Bunotherian  types  of  the  Lower  Eocene. 
So  with  the  great  divisions  of  Ungulata ;  Prohoscidians,  Hyrax, 
and  the  even-  and  odd-toed  orders  must  all  be  traced  to  the  un- 
specialized  AmUijpoda,  with  small  brains  and  five-toed  plantigrade 
feet,  as  their  ancestors.*  It  is  easy  to  perceive  that  the  generali- 
zation and  plasticity  of  all  these  forms  has  furnished  the  ground 
of  their  ancestral  relation. 

"We  are  now  in  a  position  to  comprehend  more  clearly  the 
general  nature  of  evolution.     The  doctrine  of  the  unspecialized 

*  See  the  origin  of  types  of  Mammalia  educabilia,  "  Journal  Academy,"  Philadel- 
phia, 1874. 


234:  GENERAL  EVOLUTION. 

teaches  that  the  perfection  produced  by  each  successive  age  has 
not  been  the  source  or  parent  of  future  perfection.  The  types 
which  have  displayed  the  most  specialized  mechanism  have  either 
passed  away,  or,  undergoing  no  change,  have  witnessed  the  prog- 
ress and  ultimate  supremacy  of  those  which  were  once  their  infe- 
riors. This  is  largely  true  of  animals  which  have  attained  great 
bulk.  Like  those  with  perfected  weapons,  they  have  ever  been 
superior  to  the  attacks  of  other  animals  in  their  day,  and  doubt- 
less led,  so  long  as  food  abounded,  lives  of  luxurious  indolence. 
With  change  or  diminution  of  food,  such  huge  beasts  would  be 
the  first  to  succumb,  and  it  is  a  fact  that  no  type  of  land  animals 
has  maintained  great  size  through  many  geologic  changes.  It  is 
true  that  all  of  the  lines  of  ancestry  of  the  existing  higher  Mam- 
malia, as  the  subdivisions  of  the  Carnivora,  Ungulata,  and  Quad- 
rumana,  which  we  know  in  detail,  commenced  with  types  of 
small  size  and  correspondingly  little  muscular  power. 

Some  important  conclusions  may  be  derived  from  what  has 
preceded.  It  seems  that  evolution  has  witnessed  a  continual  run- 
ning down  of  types  to  their  great  specialization  or  extinction. 
That  many  types  have  arisen  in  weak  and  small  beginnings,  but 
that  the  conflict  with  more  powerful  forms  has  developed  some 
qualities  in  which  they  sooner  or  later  excelled,  and  which  formed 
the  basis  of  their  future  superiority  and  persistence.  That  while 
this  has  probably  been  the  true  cause  of  the  origin  of  the  many 
admirable  mechanical  adaptations  displayed  by  animals,  it  is  pre- 
eminently true  of  the  development  of  mind.  That  the  reason 
why  progress  has  reached  its  limit  in  the  lines  of  greatest  speciali- 
zation, has  probably  been  the  removal  of  the  occasion  of  its  origi- 
nal cause,  i.  e.,  active  exercise  in  the  struggle  for  existence.  This 
explanation  is  suggested  by  the  remarkable  degradation  which  is 
witnessed  in  animals  whose  mode  of  life  relieves  them  from  the 
necessity  of  working  for  a  livelihood,  e.  g.,  the  parasites  and  ses- 
sile animals  whose  young  are  free.  Some  of  these  creatures,  on 
assuming  their  parasitic  life,  lose  the  semblance  of  even  the  order 
to  which  their  young  belong.  The  primary  stages  of  various 
plants  move  acti^^ely  through  the  water  like  the  lowest  forms  of 
animals,  and  their  sessile  adult  condition  must  be  looked  upon  as 
a  degeneration.  It  is  well  known  that  the  endeavor  to  relegate 
the  lowest  forms  of  life  to  the  two  kingdoms  of  animal  and  vege- 
table, has  been  generally  abandoned.  The  great  vegetable  king- 
dom probably  exhibits  a  life  degraded  from  more  animal-like  be- 


KEVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.     235 

ginnings.  Animal  irritability  and  mobility  have  been  lost,  and 
their  own  consciousness  must  be  entirely  eliminated  from  the 
question  of  the  origin  of  the  many  later  and  specialized  types  of 
plants.  But  I  venture  here  the  hypothesis  that  the  consciousness 
of  plant-using  animals,  as  insects,  has  played  a  most  important 
part  in  modifying  the  structure  of  the  organs  of  fructification  in 
the  yegetable  kingdom.*  Certain  it  is  that  insects  have  been 
effective  agents  in  the  preservation  of  certain  forms  of  plants.  I 
would  suggest  whether  the  mutilations  and  strains  they  have  for 
long  periods  inflicted  on  the  flowering  organs,  may  not,  as  in  some 
similar  cases  in  the  animal  kingdom,  have  originated  peculiarities 
of  structure. 

Evolution  of  living  types  is  then  a  succession  of  elevations  of 
l^latforms  on  which  succeeding  ones  have  built.  The  history  of 
one  horizon  of  life  is,  that  its  own  completion  but  prej^ares  the 
way  of  a  higher  one,  furnishing  the  latter  with  conditions  of  a 
still  further  development.  Thus  the  vegetable  kingdom  died,  so 
to  speak,  that  the  animal  kingdom  might  live  ;  having  descended 
from  an  animal  stage  to  subserve  the  function  of  food  for  animals. 
The  successive  types  of  animals  have  first  stimulated  the  develop- 
ment of  the  most  susceptible  to  the  conflict  of  the  struggle  for 
existence,  and  afterward  furnished  them  with  food.  Doubtless, 
in  the  occupation  of  the  world's  fields,  the  easiest  and  nearest 
at  hand  have  been  first  occupied,  and  successively  those  which 
were  more  difficult.  The  digging  animals  are  generally  those 
which  first  abandoned  the  open  field  to  more  courageous  or 
stronger  rivals  ;  and  they  remain  to  this  day  generally  of  low  type 
compared  with  others  of  their  classes  (e.  g.,  Monotremata,  Roden- 
Hay  Insectivora).  All  occupations  have  been  filled  before  that  one 
which  requires  the  greatest  expenditure  of  energy,  i.  e.,  mental 
activity.  But  all  other  modes  of  life  have  fallen  short  of  this  one 
in  giving  the  supremacy  over  nature. 

Automatism  then  represents  a  condition  of  ^'lapsed  intelli- 
gence" and  diminished  life.  The  unconscious  automatism  of 
animals  is  a  condition  of  still  greater  lapse.  On  the  contrary, 
sensibility  is  the  condition  of  development,  and  the  susceptibility 
and  impressibility  which  is  the  extreme  reverse  of  automatism  is 
the  especial  character  of  youth.  Here  the  "  doctrine  of  the  un- 
specialized"  finds  justification  again. 

*  This  opinion  has  also  been  expressed  by  Hermann  Miillcr. 


236  GENERAL  EYOLUTIOK 

What  the  future  has  in  store  for  us  in  the  history  of  inorganic 
force  and  its  results  we  can  not  now  foresee,  but  I  call  attention 
in  this  connection  to  the  important  part  played  by  life  in  the  dis- 
tribution of  minerals.  It  has  long  been  known  that  the  carbon  of 
the  earth's  crust  was  once  in  a  living  state,  and  it  is  admitted  that 
the  limestone  once  circulated  in  the  fluids  of  animals.  We  have 
recently  been  compelled  to  believe  that  siliceous  rocks  are  com- 
posed of  the  consolidated  shells  of  minute  plants,  which  they  have 
elaborated  from  the  water  of  the  ocean.  Silver  and  gold  are  seg- 
regated and  deposited  by  seaweeds.  The  principal  rock  material, 
whose  relation  to  life  has  not  been  ascertained,  is  alumina.  How 
far  the  processes  which  now  characterize  dead  matter  were  once 
related  to  life  is  a  problem  for  the  future. 

IV.    THE   MORALS   OF   EVOLUTION?". 

The  doctrines  of  the  struggle  for  existence  and  survival  of  the 
fit  in  human  life  have  a  two-fold  application.  The  relative  pro- 
portions in  which  these  applications  are  made  will  depend  on  the 
moral  development  of  him  who  makes  them.  Moral  density  and 
intellectual  stupidity  (often  nearly  allied)  will  see  in  these  two 
laws  only  the  struggle  for  material  power,  and  the  survival  of  the 
strongest.  They  will  hardly  urge  in  these  days,  as  they  would 
infallibly  have  done  had  they  lived  a  few  centuries  ago,  that  the 
strongest  means  the  hardest  hitter,  or  the  most  successful  assassin, 
but  they  will  probably  believe  that  this  pre-eminent  ]oosition  be- 
longs to  the  most  wealthy.  From  a  purely  dynamical  standpoint 
this  position  is  correct,  yet  it  might  be  a  useful  question  for  such 
advocates  to  consider  why  it  is  that  physical  oppression  and  assas- 
sination should  be  less  successful  avenues  to  power  than  they  once 
were. 

There,  are  two  reasons  why  man  does  not  grant  the  first  place 
in  his  esteem  to  physical  force.  The  first  principles  of  morals  are 
acquired  in  the  struggle  for  existence*  The  idea  of  meum  and 
tuujYi  was  speedily  developed  so  soon  as  men  associated  together ; 
and  the  habit  of  justice  has  doubtless  been  formed  by  the  insist- 
ence of  every  man  on  his  own  rights,  and  by  the  power  of  combi- 
nations of  men  to  control  those  who  may  from  superior  strength 
or  other  cause  seek  to  violate  the  rights  of  property.  Thus  law 
originated,  and  from  the  earliest  history  of  the  race  to  the  present 
day  it  has  educated  the  barbarous  and  semi-barbarous  to  civiliza- 
tion.    It  is  then  easy  to  perceive  that  man  gives  the  highest  place 


EEVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.     237 

in  his  affections  to  the  most  just ;  but  there  is  yet  another  reason 
why  this  should  be  the  case. 

The  reproductive  instinct  in  the  lower  animals  has  developed 
into  social  affections,  and  these  form  a  part  of  the  character  of 
the  higher  animals  and,  in  an  especial  degree,  of  man.  The  senti- 
ments of  sympathy  and  benevolence  are  j^robably  outgrowths  of 
the  same.  While  the  rational  faculties  are  concerned  in  the 
knowledge  of  right,  these  sentiments  are  a  source  of  the  love  of 
right.  This  disposition  is  trusted  by  men  as  leading  to  ihQ  prac- 
tice of  right,  in  cases  where  the  power  to  enforce  it  is  not  immedi- 
ately present.  The  struggle  for  existence  then  among  men  ranges 
all  the  way  from  a  rivalry  of  physical  force  to  a  rivalry  for  the 
l")OSsession  of  human  esteem  and  affection.  The  robber  and  assas- 
sin of  the  lowest  human  races  are  represented  by  the  slanderer  and 
defamer  in  the  higher.  The  ultimate  prosperity  of  the  just,  as- 
serted and  foretold  by  prophets  and  poets,  is  but  a  forecast  of  the 
doctrine  of  the  survival  of  the  fittest.  The  unjust  are  sooner  or 
later  eliminated  by  men  from  their  society,  either  by  death,  seclu- 
sion, or  ostracism. 

But  the  organized  moral  qualities  can  not  normally  transcend 
in  power,  as  motives  of  human  action,  those  which  secure  man's 
physical  preservation.  Lines  of  men  in  whom  the  sympathetic  and 
generous  qualities  predominate  over  the  self-preservative,  must 
inevitably  become  extinct.  Evolution  can  produce  no  higher  de- 
velopment of  the  race  (whatever  may  sometimes  appear  in  indi- 
viduals) than  an  equivalency  in  these  two  classes  of  forces.  Be- 
yond this  the  organization  of  the  social  faculties  of  the  brain  must 
always  be  repressed  in  the  race,  so  that  we  can  only  expect  to 
attain  an  equilibrium  between  them  and  the  more  purely  selfish 
ones,  as  the  very  highest  result  of  unassisted  evolution.  In  this 
position  the  judgment  is  suspended  between  the  opposing  classes 
of  motives ;  and  it  must  ever  remain  doubtful  in  general  as  to 
whether  resulting  action  will  be  just  and  right,  or  the  reverse.  I 
exclude  from  this  question  those  generous  acts  which  do  not  appear 
to  the  actor  to  conflict  with  self-interest.  These  may  be  termed 
sympathetic  acts,  and  are  quite  distinct  from  the  altruistic*  The 
sympathetic  actions  are  seen  at  times  in  most  animals.  The  al- 
truistic acts,  on  the  other  hand,  are  those  that  express  what  is  usu- 
ally called  ''moral  principles."      Sach  acts  may  often  coincide 

*  "  On  the  Origin  of  the  Will."    "  Penn  Monthly,"  1877. 


238  GENERAL  EVOLUTION. 

with  the  interest  of  the  actor,  but  so  long  as  they  do  not  appear 
to  him  to  do  so,  they  are  altruistic.  It  is  part  of  the  doctrine  of 
evolution  that  habits  will  ultimately  disappear  on  the  removal  of 
their  stimulating  cause.  The  moral  nature  originated,  and  has 
been  maintained,  through  the  pressure  of  the  fear  of  consequences. 
The  removal  of  this  pressure,  through  the  acquisition  of  power, 
would  then  ultimately  result  in  the  diminution  or  loss  of  the  moral 
nature,  through  disuse.  The  abuses  of  power  are  well  known. 
This  appears  to  be  all  that  evolution  can  do  for  us  in  the  produc- 
tion of  the  moral  nature.  So  it  would  appear  that  no  organized 
faculty  of  self-sufficient  altruistic  justice  can  be  derived  by  the 
process  of  mental  evolution.  The  result  is  rather  a  continued 
struggle  between  justice  and  injustice.  It  is,  then,  evident  that 
any  power  which  shall  cause  the  permanent  predominance  of  the 
just  over  the  selfish  faculties  must  be  derived  from  without. 

After  we  omit  from  customary  religion,  cosmogony,  which  be- 
longs to  science,  and  theogony,  which  belongs  to  the  imagination, 
we  have  left  an  art  which  has  for  its  object  the  development  and 
sustentation  of  good  works  or  morals  among  men.  If  the  teachers 
and  professors  of  this  art  produce  the  results  in  this  direction  at 
which  they  aim,  their  great  utility  must  be  conceded  by  all.  Their 
method  has  the  advantage  over  that  of  the  law,  in  being  of  the 
character  of  inducements  supplied  before  action,  instead  of  pains 
and  penalties  inflicted  after  action.  They  strive  to  originate  good 
conduct,  rather  than  to  punish  bad  conduct.  They  are  working 
on  the  side  of  the  originative  force  in  development,  rather  than 
the  destructive  ;  the  '^origin  of  the  fittest  y^'  rather  than  the  '^sur- 
vival of  the  fittest.  ^^  Whether  man  possesses  the  spontaneous  power 
called  '*free  will "  or  not,  the  work  of  supplying  inducements  for 
good  conduct  is  most  useful  to  society.  But  religion,  as  generally 
understood,  pre-supposes  free  will ;  and  the  definition  of  the  word 
responsibility  implies  its  existence.  The  question  as  to  the  pres- 
ence of  such  a  faculty  is  an  interesting  one,  and  will  now  be  briefly 
considered. 

The  well-known  doctrine  of  necessity  leaves  no  j^lace  for  free 
will.  All  acts  are  the  consequences  of  motives,  and  are  the  out- 
come of  a  balancing  of  interests.  The  heaviest  side  of  the  account 
determines  action.  Our  physical  necessities  supply  the  motives 
for  most  of  our  activities  ;  our  pursuit  of  food  and  clothing  is  of 
necessity,  and  no  condition  is  free  from  it.  Evolution  supports 
and  explains  this  doctrine,  as  can  readily  be  perceived.     It  de- 


EEVIEW  OF  THE  MODERN  DOCTRINE  OF  EVOLUTION.     239 

rives  our  instincts  from  an  ancestry  whose  daily  occupation  has 
been  their  gratification.  But  it  has  been  shown  above  that  this 
development  does  not  supply  the  motives  of  an  independent 
morality.  * 

The  direction  of  action  under  stimulus  is  determined  by  intel- 
ligence, which  is,  as  has  been  above  maintained,  the  product  of 
experience.  Intelligence  is  organized  or  classified  knowledge,  and 
directs  the  activities  set  on  foot  by  the  likes  and  dislikes,  that  is, 
the  affections.  When  there  is  knowledge,  there  is  no  necessity  for 
spontaneous  action  or  free  will,  since  action  is  determined  by  the 
organization  of  the  mind.  Even  if  the  mind  is  conscious  of  insuf- 
ficient knowledge,  an  inducement  to  seek  knowledge  is  supplied, 
and  according  to  the  result  of  investigation  will  be  the  direction 
of  knowledge. 

But  we  are  here  brought  to  face  the  case  where  knowledge  can 
not  be  or  is  not  obtained.  This  is  the  condition  of  the  two  ques- 
tions of  the  practice  of  morals,  and  the  nature  of  the  future  life. 
The  evolution  of  mind  consists  of  a  continual  advance  from  the 
known  into  the  unknown,  and  a  transfer  of  the  unknown  to  the 
known.  So  long  as  there  is  any  inducement  to  progress  of  this 
kind,  and  nature  responds  to  inquiry,  development  will  go  on.  Al- 
though it  is  true  that  it  is  only  among  men,  and  but  few  men  at 
that,  that  the  pursuit  of  knowledge  is  an  occupation,  most  men 
add  to  their  stock  incidentally  as  they  pursue  other  avocations. 
The  knowledge  of  right  and  the  inducements  to  its  practice  are 
learned  in  their  every-day  intercourse,  so  far  as  it  can  be  acquired. 
But  knowledge  in  these  directions  soon  attains  its  limit,  and  ac- 
cordingly, development  dependent  on  knowledge  must  cease.  If 
any  further  progress  in  practical  morals  is  to  be  made,  some  new 
force  must  intervene  at  this  point. 

Here  is  the  opportunity  for  the  appearance  of  will  or  sponta- 
neity ;  here  it  is  at  least  needed.  I  am  willing  to  believe  that  it 
may  appear  at  this  point,  and  that  so  long  as  we  have  to  face  the 
unknown  in  moral  progress,  so  long  it  will  remain.  As  a  force 
it  must  be  equivalent  of  other  forces,  but  as  a  form  of  conscious- 
ness it  is  a  new  element  of  mind.  As  represented  in  new  molecu- 
lar organization,  it  may  always  continue,  even  after  much  of  the 
unknown  may  have  been  conquered,  and  a  stationary  period  may 
have  ensued.     Such  an  accession  to  character  would  be  a  fitting 


*  "  On  the  Origin  of  the  Will."    "  Penn  Monthly,"  ISVY. 


240  GENERAL  EVOLUTION. 

crown  of  eyolution,  and  a  justification  of  this  labor  of  the  ages. 
If  a  true  factor  in  human  development,  it  might  be  compared,  in 
the  creation  of  character,  to  the  apical  bud  of  a  growing  tree.  As 
the  part  pre-eminently  living,  it  leads  the  growth  of  the  trunk  and 
branches.  They  all  follow  of  necessity  the  path  it  has  marked  out. 
Under  its  lead  they  are  successively  formed,  become  fixed,  and 
finally  decay. 


PART  II. 

THE   STEUOTUEAL  EYIDEI^^CE   OF 

EYOLUTIO]^. 


VII. 

ON  THE  HOMOLOGIES  AND  ORIGIN  OF  THE  TYPES 
OF  MOLAR  TEETH  OF  THE  MAMMALIA  EDUCA- 
BILIA. 

I.    THE   TYPES   OF   MAMMALIAN   MOLARS. 

It  has  been  already  stated  *  that  the  transition  from  simple  to 
complex  teeth  is  accomplished  by  repetition  of  the  type  of  the 
former  in  different  directions.  ^^In  the  cetaceans  this  occurs  in 
the  Squalodonts  ;  the  cylindric  incisors  are  followed  by  flattened 
ones,  then  by  others  grooved  in  the  fang,  and  then  by  two-rooted, 
but  never  by  double-crowned  teeth.  This  is  the  result  of  antero- 
posterior repetitive  acceleration  of  the  simple  cylindric  dental  type 
of  the  ordinary  toothed  cetacean.  Another  mode  of  dental  com- 
plication is  by  lateral  repetition.  Thus  the  internal  heel  of  the 
superior  sectorial  tooth  of  a  carnivore  is  supported  by  a  fang 
alongside  of  the  usual  posterior  support  of  a  premolar,  and  is  the 
result  of  a  repetitive  effort  of  growth-force  in  a  transverse  direc- 
tion. More  complex  teeth,  as  the  tubercular  molars,  merely  ex- 
hibit an  additional  lateral  repetition,  and  sometimes  additional 
longitudinal  ones.  As  is  well  known,  the  four  tubercles  of  the 
human  molar  commence  as  similar  separated  knobs  on  the  [primi- 
tive] dental  papilla." 

Accordingly,  the  simple  tubercle  may  be  regarded  as  the  least 
specialized  form  of  tooth.  It  may  be  low  and  obtuse,  as  in  the 
Cliiromys,  or  the  walrus  ;  more  elevated  and  conic,  as  in  the  dol- 


*  "  Method  of  Creation,"  p.  10.     Philadelphia,  1871. 
16 


242        THE  STRUCTURAL  EVIDEN'CE  OF  EVOLUTION. 

phins  ;  or  truncate,  as  in  sloths  and  some  rodents.  The  form  is 
complicated  in  two  ways,  viz.,  either  by  the  folding  of  the  sides, 
as  in  Glyptodon  and  many  rodents,  as  Arvicola,  Castor,  Lepus, 
etc.  ;  or  by  the  develoj^ment  of  tubercles  on  the  crown,  as  in  Mus, 
Dicotyles,  Homo,  etc.  Upon  this  basis  are  constructed  the  more 
complex  types  of  teeth  exhibited  by  the  various  families  of  Ungu- 
lata  and  some  Rodentia,  as  has  been  pointed  out  in  the  following 
language  :  '^  The  genus  Uintatlierium^  has  been  shown  to  be  a  Pro- 
boscidian, which  combines  some  important  features  of  the  Peris- 
sodadyla  with  those  of  its  own  order.  .  .  .  The  number  of  such 
characters  was  shown  to  be  somewhat  increased  in  Bathmodon, 
which  therefore  stands  still  nearer  to  the  common  point  of  de- 
parture of  the  two  orders.  This  point  is  to  be  found  in  types  still 
nearer  the  clawed  orders  {Unguiculata)  in  the  number  of  their 
digits  (4,  5),  and  in  which  the  transverse  and  longitudinal  crests 
of  the  molar  teeth  are  broken  up  into  tubercles  more  or  less  con- 
nected, either  type  of  dentition  [i.  e.,  Proboscidian  or  Perissodac- 
tyle]  being  derived  according  as  such  tubercles  are  expanded  in 
the  transverse  or  longitudinal  directions."  f 

As  is  well  known,  the  crowns  of  the  superior  molar  teeth  of 
the  higher  Mammalia  are  supported  on  three  roots,  two  of  which 
are  external,  and  the  third  internal.  The  corresponding  inferior 
molars  are  supported  on  two  roots,  and  are  therefore,  in  so  far,  less 
complex.  But  these  two  roots  usually  support  four  tubercles,  two 
to  each,  while  the  roots  of  the  superior  molars  support  directly 
but  one  each.  Hence,  as  Prof.  Harrison  Allen  remarks,  the 
crown  of  the  inferior  molar  is  more  complex  than  that  of  the  su- 
perior. \ 

In  tracing  the  degrees  of  complication  of  the  crowns  of  the 
superior  molars  of  Mammalia  from  the  simple  cone  of  the  Ceta- 
cean, the  first  step  is  seen  in  the  Squalodon  and  teeth  of  similar 
character.  In  these  there  are  two  roots,  antero-posteriorly  related. 
In  the  Squalodont  Portheodon  gervaisii  {Squalodon  Auct.)  the 
third  root  is  present.  In  Mammalia  with  but  three  tubercles  in 
the  crown,  e.  g.,  Carnivora,  the  inner  root  has  much  the  form  of 
one  of  the  external  ones.  In  many  of  those  with  four  tubercles 
of  the  crown,  e.  g.,  Qiiadrumana,  the  form  of  the  internal  root  is 

*  Eohasileus  in  the  original.     (Ed.  1886.) 

f  "  On  tlie  Primitive  Types  of  Mammalia  Educabilia,"  published  by  E.  D.  Cope, 
May  6,  1873.     "Proceedings  of  the  American  Philosophical  Society,"  1873,  p.  224. 
X  "Dental  Cosmos,"  December,  1874. 


MOLAK  TEETH  OF  THE  MAMMALIA  EDUOABILIA.     243 


not  modified  ;  but  in  the  Lophodont  types  it  is  materially  altered. 
In  Hyracodon,  RMnocerus,  Anchitherium,  Oreodon,  Cervus,  and 
others,  it  is  flattened,  with  the  long  diameter  anteroposterior,  and 
is  grooved  on  the  inner  face,  so  as  to  assume  the  form,  as  it  does 
the  function,  of  two  roots  conjoined.  In  the  temporary  dentition 
of  Bus,  Merychyus,  etc.,  the  inner  root  is  divided,  so  that  the 
superior  molar  has  four  distinct  roots. 

The  proper  homologizing  of  the  various  forms  of  dental  struct- 
ure of  the  Ungulates  with  each  other,  and  with  the  primitive 
types  of  tubercular  teeth,  is  entirely  essential  to  their  intelligent 
classification,  and  therefore  comprehension  of  their  mode  of  origin. 
In  order  to  lay  a  foundation  for  this  work,  I  define  the  four  types 
as  follows,  giving  the  subdivisions  of  the  first  two  in  brief,  and 
discussing  those  of  the  third  and  fourth  more  fully  afterward  : 
Division  I.  Haplodont  type  ;  the  crown  undivided  or  simple. 
a.  Crown  low,  obtuse;  Cetacea  {Be- 
luga), Carnivora  (Rosmarus). 
h.  Crown  elevated,  acute  ;  Cetacea 
{Delplii7ius)  ;  canine  teeth  in 
general. 
c.  Crown  truncate  ;  Edentata  {Bra- 
dy pits)  ;    Rodentia    { Qeomys, 
Dipodomys). 
Division  11.  Ptycliodont  type  ;  the  crown  folded  on  the  sides  ; 
the  folds  frequently  crossing  the  crown. 
a.  Sides    only    folded  ;    Rodentia 
(Arvicola  Castor) ;    Edentata 
^  {Glyptodon). 
h.  Summit  of  crown  also  folded ; 
Rodentia  {Lepus,  Chinchilla). 
Division  III.  Bunodont  type  ;  crown  supporting  tubercles. 
a.  Tubercles  few,    opposite  ;    TJ71- 
gulata,  Achcenodon,  Dicotyles, 
Elotherium ;  Carnivora,  Pro- 
cyon  ;  Rodentia,  Heliscomys. 
h.  Tubercles  few,  alternate  ;  Hyop- 

-,  Fio.  17. — LeptocJicerus. 

sodus. 
c.  Tubercles  numerous,  irregular  ;  Mastodon,  Phacochoerus. 
Division  IV.    Lophodont  type  ;    the   summit   of  the   crowns 
thrown  into  folds  of  transverse  or  longitudinal  direction.    Higher 
Ungulates. 


Fig.  15. —  Glohicephalus. 


Fig.  16. — Jaculus  hudsonicus. 


244        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 


This  division  embraces  the  many  types  observed  in  the  Ungu- 
lates, some  Rodents,  and  possibly  Garni vora.  Inasmuch  as  the 
teeth  of  the  maxillary  and  dentary  (mandibular)  bones  do  not  al- 
ways conform  to  the  same  type  (e.  g.,  Symborodo7i,  Equus),  it 
will  be  necessary  to  consider  them  separately.  Besides  the  differ- 
ence in  type,  they  differ  in  their  rela- 
tive development  in  width  in  the 
more  specialized  forms ;  thus,  in 
Homo,  Mus,  Mastodon,  and  such 
genera,  the  molars  of  both  jaws  are 
identical ;  in  Palceotlierium,  Eohasi- 
leus,  Tcqnrus,  etc.,  and  most  Car- 
nivora,  the  superior  are  the  wider, 
the  inferior  narrower,  appropriately 
to  the  greater  slenderness  of  the 
mandibular  bone.  The  latter,  or 
anisognathous  type,  may  then  be  regarded  as  the  more  specialized. 
The  Bunodonts,  except  some  Carnivora,  are  all  of  the  former  or 
isognathous  type  ;  among  Lophodonts  the  few  Rodents,  the  Dino- 
theriidcB,  and  Elephas  are  isognathous,  while  all  of  the  other 
Prohoseidia,  the  Perissodactyla,  and  Rumina7itia  are  anisogna- 
thous.    Examples  may  be  selected  as  follows  : 

Isognatlious ;  Bunodonts  :  Homo,  Dicotyles,  Sus,  Mastodon, 
Elotlieriiim ;  Lophodonts  :  Dmotheriidce,  Eleplias ;  Rodentia, 
JSciuridce. 

Anisognatlious  ;  Bunodonts  :  Macacus,  Lemur oidea,  Procyon  ; 
Lophodonts  :  A7iopIotherium,  Hyoj^otamus,  Oreodon,  Ruminantia, 
Perissodactyla,  Batlimodon,  TJintatlierium, 


Fig.  18. — BJiinocerus  (temporary). 


II.  THE  subordi:n"ate  types  of  bui^odojs^ts. 

1.   The  Maxillary  Teetli.^       » 

It  is  apparent  that  the  type  of  superior  molar  tooth  which  pre- 
dominated during  the  Puerco  epoch  was  triangular  or  tritubercu- 
lar  ;  that  is,  with  two  external  and  one  internal  tubercles,  f  Thus, 
of  sixty-seven  species  of  placental  Mammalia  of  which  the  suj^erior 
molars  are  known,  all  but  four  have  three  tubercles  of  the  crown, 

*  This  division  is  inserted  from  the  "  Proceedings  of  the  American  Philosophical 
Society,"  for  December,  1883,  for  the  sake  of  supplying  an  omission  in  the  original 
memoir.     (Ed.  1886.) 

f  See  "American  Naturalist,"  April,  1883,  p.  407. 


MOLAR  TEETH  OF  THE  MAMMALIA  EDUOABILIA.     245 

and  of  the  remaining  sixty-five,  all  are  triangular,  excepting  those 
of  three  species  of  Periptychus,  and  three  of  Oonoryctes,  which 
have  a  small  supplementary  lobe  on  each  side  of  the  median  prin- 
cipal inner  tubercle. 

This  fact  is  important  as  indicating  the  mode  of  development 
of  the  various  types  of  superior  molar  teeth,  on  which  we  have  not 
heretofore  had  clear  light.  In  the  first  place,  this  type  of  molar 
exists  to-day  only  in  the  insectivorous  and  carnivorous  Marsupi- 
alia  ;  in  the  Creodonta,  and  the  tubercular  molars  of  such  Carnivo- 
ra  as  possess  them  (excepting  the  i^lantigrades).  In  the  Ungu- 
lates its  persistence  is  to  be  found  in  the  molars  of  the  Corypho- 
dontidse  of  the  AYasatch,  and  Dinocerata  of  the  Bridger  Eocenes. 
In  later  epochs  it  is  occasionally  seen  only  in  the  last  superior 
molar. 

It  is  also  evident  that  the  quadritubercular  molar  is  derived 
from  the  tritubercular  by  the  addition  of  a  lobe  of  the  inner  part 
of  a  cingulum  of  the  posterior  base  of  the  crown.  Transitional 
states  are  seen  in  some  of  the  Periptychidae  {Anisonchus),  and  in 
the  sectorials  of  the  Procyonidae. 

2.   The  Mandibular  Teeth. 

The  tritubercular  or  triangular  superior  molar  is  associated 
with  a  corresponding  form  of  the  anterior  part  of  the  inferior 
molar.  This  kind  of  inferior  molar  I  have  called  the  tubercular 
sectorial,  and  is  very  variable  as  to  the  degree  of  development  of 
the  sectorial  cutting  edge.  The  anterior  triangle  is  formed  by  the 
connection  by  angle  or  crest,  of  the  median  and  anterior  internal 
crests  with  the  anterior  external.  Its  primitive  form  is  seen  in 
Didelphys,  Pelycodus,  Pantolambda  and  the  Amblypoda  gener- 
ally ;  in  Centetes  and  Talpa ;  and  in  its  sectorial  form,  in  Stypo- 
lophus  and  Oxyaena,  etc. 

The  *  tubercular  molar  of  some  ViverridcB,  and  among  the  ex- 
tinct forms  especially  the  Didymictis  protenus,  Cope,  present  a 
similar  structure  to  that  just  described.  This  furnishes  a  ready 
explanation  of  the  tooth  immediately  in  advance,  which  is  the 
primitive  form  of  sectorial  tooth  characteristic  of  primitive  Car- 
nivora.     The  three  anterior  tubercles  are  largely  developed,  stand- 


*  The  remainder  of  this  section  (2)  is  taken  from  the  writer's  "  Synopsis  of  the 
Vertebrata  of  the  Eocene  of  New  Mexico,"  p.  800.  Publication  of  the  U.  S.  G.  G. 
Survey,  W.  100th  Meridian,  1875.     (Ed.  1886.) 


246        THE  STRUCTUKAL  EVIDENCE  OF  EVOLUTION. 

ing  at  opposite  angles  of  a  triangular  space  ;  the  outer  and  ante- 
rior cusps  are  the  most  elevated,  and  the  ridge  which  connects 
them  is  now  a  cutting  blade.  The  posterior  portion  of  the  tooth 
does  not  share  in  this  elevation,  and  its  two  tubercles  are  in  some 
genera  obsolete,  and  in  others  replaced  by  an  elevation  of  one  mar- 
gin, which  leans  obliquely  toward  the  middle  of  the  crown.  In 
Mesonyx  this  is  represented  by  a  median  longitudinal  crest.  If 
the  two  tubercles  of  the  posterior  part  oi  this  tooth  (which  may  be 
termed  a  tubercular  seciorial)  are  elevated  and  acute,  we  have  the 
molar  of  many  recent  and  extinct  Insectivora  ;  if  the  same  por- 
tion (now  called  a  lieel)  is  much  reduced,  we  have  the  type  of 
Oxycena  and  Stypolo2)lius.  In  the  Canidce  the  three  anterior  tu- 
bercles are  much  less  elevated  than  in  the  genera  above  named  ;  the 
external  is  much  the  larger,  and  the  anterior  removed  farther  for- 
ward so  as  to  give  the  blade  a  greater  antero-posterior  extent. 
The  heel  is  large  and  without  prominent  tubercles.  In  the  Muste- 
lidm  the  inner  of  the  two  median  cusps  is  often  reduced  to  a  rudi- 
ment, or  is  entirely  wanting,  and  the  heel  is  large.  The  lower 
sectorial  of  the  HycenidcB  has  no  inner  tubercle,  and  the  heel  is 
much  reduced.  In  some  of  the  saber-toothed  tigers  the  heel  re- 
mains as  a  mere  rudiment,  while  in  the  true  cats  it  has  entirely 
disappeared,  and  the  carnassial  tooth  remains  perfected  by  sub- 
traction of  parts,  as  a  blade  connecting  two  subequal  cusps.  The 
HycBnodontidcB,  as  is  known,  possess  three  carnassial  teeth  without 
inner  tubercles.  The  history  of  this  form  is  as  yet  uncertain,  as 
it  was  evidently  not  derived  from  contemporary  forms  of  the 
Eocene  with  tubercular  sectorials. 

The  development  of  the  inferior  carnassial  dentition  has  thus 
been  accomplished  by  the  subtraction  of  the  inner  and  posterior 
cusps,  so  that  of  the  original  four  of  the  quinquetuberculate  molar 
but  a  single  one,  i.  e.,  the  anterior  external,  remains. 

III.    THE   SUBORDIjq-ATE    TYPES   OF   LOPHODOXTS. 

1.   The  Maxillary  Teeth, 

In  the  essay  already  quoted  *  the  following  remarks  (page  7) 
explain  the  relation  between  the  Bunodont  genera  and  several  of 
the  Lophodont  types  of  superior  molar  teeth  :  "In  the  superior 

*  "Primitive  Types  of  Mammalia  Educabilia,"  May,  1873,  and  Hayden's  "Re- 
port on  Geological  Survey  of  Montana,  Wyoming,  etc.,"  ISYS,  p.  646. 


MOLAR  TEETH   OF  THE  MAMMALIA  EDUCABILIA.     247 

molar  series  the  flattening  of  the  outer  tubercles  may  proceed  so 
far  as  to  produce,  on  wearing,  a  confluence  of  the  [resulting]  cres- 
centoid  surfaces.  ...  In  both  PalcBOsyops  and  Hyrachyus  these 
tubercles  of  the  upper  molars  are  confluent  into  two  Vs  (more  or 
less  open  when  unworn).  In  the  former  the  inner  tubercles  retain 
their  primitive  conic  tubercular  form,  but  in  Palceotheriwn,  EJii- 
nocerus,  Lopliiodon^  Hyrachyus,  and  Tapirus  they  elongate  trans- 
versely so  as  to  meet  the  corresponding  outer  tubercles  (now  crests) 
forming  the  familiar  cross-crests  of  those  genera.  If  alternate, 
the  oblique  crests  of  Palceotheriuyn  ;  if  opposite,  the  cross-crests 
of  Tapirus.  If,  on  the  other  hand,  the  inner  tubercles  flatten  like 
the  outer,  we  have,  on  wearing,  the  quadricrescentoid  [Selenodont] 
type  of  the  Ruminantia  and  Anoplotlierium:  In  the  Quadruma- 
nous  families,  including  man,  the  primitive  quadrituberculate  type 
of  molars  is  preserved." 

Four  types  of  Lophodont  dentition  are  included  in  the  above 
discussion,  and  three  others  may  be  added.  They  belong  to  two 
series,  viz.,  those  in  which  the  crests  represent  the  modification 
of  opposite  tubercles,  and  those  where  the  tubercular  elements  of 
the  crown  are  alternate.  These  series  may  be  called  the  Ammho- 
dont  (alternate),  and  Antiodont  (opposite),  and  the  component 
types  are  : 

Antiodoj5"ts. — Selenodont  (Ruminants)  ;  Tapir odont  {Tapir, 
Rhinoceriis)  ;  Trichecliodont  (Manati,  Elephant). 

Amcebodokts. — PalcBotheriodont  (Palasotherium,  etc.)  ;  Sym- 
lorodont  (Palaeosyops  Symborodon,  etc.)  ;  Batlimodont  (Bathmo- 
don,  etc.)  ;  Loxolopliodont  (Uintatherium,  etc.). 

These  types  are  defined  as  follows  : 

1.  Antiodoxts. 

Sele7iodonts.—T\\Q  tubercles  separate  or  united  at  their  angles, 
much  elevated,  narrow  crescentic  in  section,  separated  by  deep 
valleys. 

To  this  group  belong  the  molars  of  the  Euminants,  the  Tra- 
gulidce,  the  Oreodontidm,  and  Mery copotamido ;  of  Perissodac- 
tyles  the  EquidcB. 

Tapir odo7its.— The  outer  tubercles  longitudinally  compressed, 
subcrescentic  in  section  ;  the  inner  transversely  compressed,  con- 
tinued as  transverse  ridges  to  the  end  or  middle  of  the  correspond- 
ing exterior  crests. 

RUnocerus,  Tapirus,  Hyrachyus,  LopUodon,  and  Hyrax  rep- 


248        THE  STRUCTURAL  EVIDENCE   OF  EYOLUTIOX. 

resent  this  type  ;  the  last  molar  of  LopModon  appears  to  be  Attkb- 
lodont, 

Tricliecliodonts. — Tubercles  confluent  into  two  or  more  trans- 
verse crests. 

The  Dinotherium  represents  this  form,  so  does  Eleplias,  Tri- 
checus  (the  manati),  and  a  number  of  the  larger  Marsupialia. 

2.  Amcebodonts. 

PalcBotheriodonts. — External  tubercles  longitudinal,  subcres- 
centic  in  section  ;  the  inner  united  with  them  by  transverse  oblique 
crests. 

Palceotherium  and  Ancliitlierium  present  this  type,  which  only 
differs  from  the  Tapirodont  in  the  alternation  of  the  opposing 
tubercles. 

Syniborodonts. — External  tubercles  longitudinally  compressed 
and  subcrescentic  in  section  ;  the  inner  indejDendeut  and  unal- 
tered, i.  e.,  conic. 

To  this  group  are  to  be  referred  the  types  of  Palcsosyops,  Me- 
nodus,  and  Symhorodon.  They,  of  all  Lopliodonts,  approach  near- 
est to  the  Bunodonts, 

Bathmodonts. — The  posterior  pair  of  tubercles  approximated 
and  connected,  together  compressed  and  subcrescentoid  in  section  ; 
the  anterior  outer  connected  with  the  anterior  inner  by  an  oblique 
crest  forming  a  V  with  the  preceding. 

Bathmodon  and  Metalopliodon. — The  homologies  of  the  crests 
are  difficult  to  make  out ;  the  subcrescentic  crest  of  the  second 
molar  may  include  only  the  posterior  outer  tubercle,  and  thus  be 
entirely  homologous  with  the  posterior  crescent  of  Palseosyops.  In 
support  of  this  view  we  have  the  structure  of  the  premolars,  where 
it  becomes  the  only  external  crescent,  while  the  anterior  transverse 
crest  turns  round  on  its  inner  side,  supporting  the  inner  anterior 
tubercle  of  the  tooth.  [Note  to  this  edition  :  The  latter  view  is 
the  correct  one,  as  the  posterior  inner  tubercle  is  wanting.] 

Loxolopliodonts — Anterior  inner  tubercle  connected  with  the 
two  external  by  oblique  crests  ;  the  posterior  inner  tubercle  rudi- 
mental  or  wanting. 

Uintatherium  and  probably  Tillotherium  represent  this  group, 
both  being  like  those  of  the  last,  extinct  genera  from  the  Eocene 
of  Wyoming. 


MOLAR  TEETH   OF  THE  MAMMALIA  EDUCABILIA.    249 


•  2.   Tlie  Mandibular  Teeth, 

The  types  of  structure  are  less  numerous  than  those  of  the 
maxillary  teeth,  since  I  am  only  acquainted  with  six.  Still  more 
distinctly  than  those  of  the  upper  jaw  do  they  represent  the  types 
of  opposite  or  alternating  tubercles,  or  the  antiodont  and  amoebo- 
dont.  The  essential  principles  of  modification  are  the  same  as  in 
the  maxillaries,  and  they  correspond  with  them  as  to  genera,  as 
follows  : 

Aktiodont. 


Inferior. 

Selenodont. 
Hyracodont. 

Trichecodont. 


Superior. 

Selenodont. 

Tapirodont  pt. 
j  Tapirodont  pt. 
(  Trichecodont. 


Amcebodoxt. 

J  Palaeotheriodont. 

■  I  Symborodont. 

Selenodont  pt. 

j  Bathmodont. 

(  Loxolophodont. 

The  characteristics  of  these  groups  are  as  follows  : 

A.  Antiodonts. 


Symborodont. 

Hippodont. 

Loxolophodont. 


Selenodonts. — Constructed,  typically,  like  the  upper  molars, 
Rummantia. 

Hyracodonts, — External  tubercles  compressed  longitudinally 
and  crescentic  in  section,  continuous  by  a  cross-crest  with  the  cor- 
responding tubercle  of  the  iuner  side. 

The  animals  which  possess  this  type  of  teeth  are  the  Bliinoce- 
riiSj  Hyracodon,  and  the  Hyrax  ;  it  is  nearly  approached  by  some 
of  the  Hyrachyi.  It  corresponds  in  structure  with  the  true  tapiro- 
dont arrangement  of  the  maxillary  teeth  ;  but  many  of  the  Ta^^iro- 
donts  have  the  Trichecodont  type  of  mandibular  teeth. 

Trichecodonts. — Definition  the  same  as  for  the  maxillary  teeth. 

Tapirus,  LopModo7i,  Hyracliyus,  Dinotlierium,  Eleplias,  Tri- 
checus  (the  manati),  and  the  Kangaroos  and  their  extinct  allies 


belong  here. 


B.  Amcebodonts. 


Hippodonts. — In   the   horses   the   maxillary  molars   are   con- 
structed on  an  opposite  crested  basis,  while  the  mandibulars  repre- 


250        THE  STRUCTURAL  EYIDEII^OE  OF  EVOLUTION". 

sent  an  alternate  crested  type.  This  is  not  constituted  as  in  the 
next  form,  by  a  union  of  alternating  tubercles,  but  as  in  the  Sele- 
nodonts  by  the  special  deyelo^Dment  of  each  crest  into  a  crescent 
extended  antero-posteriorly.  As  alternating,  the  inner  crescents 
stand  at  the  apices  of  the  outer,  and  are  connected  with  them. 
In  Ancliitherium  the  inner  are  so  reduced  as  to  constitute  a  condi- 
tion intermediate  between  the  Hippodont  and  Syiiiborodont  types. 

Syniborodonts.  —  The  alternating  tubercles  connecting  by 
oblique  ridges  which  form  together  two  Vs. 

To  this  type  is  to  be  referred  a  great  number  of  Perissodac- 
tyles,  e.  g.,  Anchitheiium,  Palceotherium,  Falmosyops,  Menodus, 
Syiiiborodon,  A  ncMppodus. 

Loxolopliodonts. — Alternate  cusps  connected  by  two  cross 
ridges  from  the  outside  forward  and  one  from  the  inside  forward  ; 
from  which  result  an  oblique  posterior  cross  ridge,  and  a  V  open- 
ing inward. 

Here  are  Eohasileus  and  Batlimodon- ;  the  last  molar  of  the 
latter  having  the  anterior  ridge  of  the  V  quite  low. 

S.   Comparison  of  the  Opposing  Series. 

In  review,  the  above  types  of  molar  dentition  may  be  classified 
as  follows,  with  reference  to  the  amount  or  complication  of  the 
modification  of  the  tubercular  type.  The  orders  of  Ungulata  with 
which  they  correspond,  are  also  given. 

a.  Both  inner  and  outer  tubercles  crescentoid. 

JRuminantia. 
(Anoplotheintim,  Oreodon,  Hyopotamus). 
Perissodactyla  (Equidce). 
13.  External  tubercles  only  crescentoid ;  the  inner  transverse 
or  tubercular. 
Tapirodonts.  j 

Palaeotheriodonts.  >•         Perissodactyla  in  gen. 
Symborodonts.        ) 

y.  Neither  kind  of  tubercles  crescentoid,  but. united  in  pairs. 
Trichecodonts.  Prohoscidia. 

It  may  be  added  that  the  groups  arranged  under  y  are  the 
only  ones  in  which  the  types  of  crests  of  the  superior  and  inferior 
molars  are  fundamentally  simple  and  alike.  Thus  in  the  group 
a,  tubercles  of  both  upper  and  lower  series  are  modified  indeiDcnd- 
ently  to  produce  the  type  ;  in  group  (3,  the  tubercles  of  the  upper 
series  are  modified  independently  of  each  other,  while  those  of  the 


MOLAR  TEETH  OF  THE  MAMMALIA  EDUCABILIA.    251 

inferior  series  unite,  in  order  to  produce  the  result ;  in  diyision 
y  the  tubercles  of  both  jaws  unite  entirely  across  the  crown,  with- 
out any  distinction  between  those  of  the  outer  and  inner  sides. 
Thus  the  molar  type  of  dentition  of  the  Proboscidians  is  the  most 
generalized  among  the  Lophodonts,  resembling  in  this  respect  the 
type  of  construction  of  the  feet. 

lY.    THE   ORIGIK   OF   THE   MODER]S"   TYPES    OF   BUKODOKT   AKD 

L0PH0D02iT   DENTITIOi^. 

The  four  types  of  molar  dentition,  the  Haplodont,  Ptycho- 
dont,  Bunodont,  and  Lophodont,  are  by  no  means  sharply  de- 
fined, but  pass  into  each  other  by  insensible  gradations  at  many 
points.  The  addition  of  cusps  to  the  simple  cone  has  been 
accomplished  by  the  appearance  of  folds  at  the  base  of  the 
crown,  which  have  increased  in  size  so  as  to  resemble  the  primi- 
tive cusp  to  which  they  are  attached.  As  already  pointed  out, 
the  first  additional  cusp  in  the  transverse  direction  appears  on  the 
inner  side  of  the  first,  or  anterior  cusp.  The  last  one  was  ap- 
parently the  inner  posterior.  I  first  consider  the  carnassial  mo- 
lars. 

1.   Tlie  Carnassial  Bunodo7its. 

In  tracing  the  appearance  of  the  different  types  of  superior 
sectorial  in  time,  the  following  facts  are  patent  :  In  the  Eo- 
cene genera  Mesonyx,  AmUyctonus,  Oxymna,  Stypolophus,*  etc., 
the  inner  tubercle  is  much  more  largely  developed  than  in  any  ex- 
isting Carnivora,  with  the  exception  of  some  of  the  Viverridce.  In 
all,  the  sectorial  crowns  are  less  efficient  as  shear-like  cutters  than 
in  Canidce,  Mustelidce,  Hycenidm,  and  Felidce,  on  account  of  the 
shortness  of  the  posterior  blade  and  the  slight  compression  of  the 
anterior  cone.  On  the  other  hand,  in  all  of  them  the  number  of 
teeth  presenting  the  carnassial  or  three-tubercled  type  is  greater 
than  in  existing  genera,  the  posterior  upper  molars  in  the  latter 
being  either  narrowly  tubercular  or  wanting.  The  genus  Hyceno- 
don,  while  agreeing  with  the  others  in  this  respect,  differs  from 
them  in  the  great  reduction  of  the  inner  cusp,  which  is  obsolete 
even  in  the  representative  of  the  true  carnassial  tooth,  although 
the  inner  root  remains  in  all.  Hence  this  type  of  dentition  might 
be  regarded  as  the  most  specialized  of  those  of  the  Carnivora, 

*  In  the  original,  the  synonym  Prototomus  is  used  here. 


252        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

but  for  the  fact  of  the  imperfection  of  the  shear  blades  in  all  ex- 
cept the  last.  This  is  seen  in  the  large  and  prominent  anterior 
cusp  and  very  short  posterior  blade. 

In  all  recent  and  most  Miocene  Carnivora,  the  sectorials  are 
reduced  to  one  in  each  jaw,  the  exception  in  the  latter  period 
being  the  genus  Hycenodon,  which  did  not  continue  later.  The 
posterior  carnassials  of  the  Eocene  forms  disappear,  and  in  the 
most  specialized  recent  families  HymnidcB^  Mustelidm,  and  Fe- 
lidcB  have  scarcely  any  representatives.  The  shortening  of  the 
series  appears  in  the  premolars  as  well,  until  we  have  the  formula 
of  the  FelidcB,  P.  m.  2  ;  M.  2. 

In  the  inferior  dentition  the  same  process  may  be  observed  in 
the  successional  modifications  of  the  entire  series.  The  Eocene 
forms  of  carnivora  frequently  display  more  numerous  sectorial 
teeth  (such  as  they  are)  than  any  of  the  existing  families.  The 
important  change,  which  is  clearly  indicated,  is  the  progressive 
extinction  of  the  genera  with  numerous  sectorial  teeth,  accom- 
panying the  increasing  specialization  of  the  sectorial  tooth  in  the 
genera  which  remain.  In  other  words,  the  numerous  types  of 
digitigrade  carnivora  which  have  survived  are  those  developing 
but  one  sectorial  tooth  (whose  earliest  rei^resentative  is  Didymic- 
Us).  The  increased  perfection  of  the  sectorial  tooth  has  been  as- 
sociated with  a  reduction  in  the  number  of  other  molars,  first, 
posterior,  then  anterior  to  it,  which  reduction  has  been  accom- 
panied by  an  increased  relative  size  of  the  sectorial.  By  this  pro- 
cess concentration  of  the  carnassial  function  has  been  gained,  and 
increased  robustness  of  the  jaws,  by  progressive  shortening.  The 
slender  form  of  the  rami  of  the  Eocene  genera  and  Hymnodon  are 
much  less  efficient  in  functional  use  than  the  stout  jaws  of  exist- 
ing MustelidcB,  Hywnidce,  and  Felidce. 

2.   The  Lopliodonts. 

Transitions  between  the  Bunodonts  and  Lopliodonts  are  very 
obvious,  so  much  so  as  to  lead  to  the  belief  that  the  several  sub- 
divisions of  the  Lopliodonts  represent  modifications  of  correspond- 
ing types  of  Bunodonts,  and  that  the  two  are  partially  '^  homolo- 
gous groups."  Both  present  corresponding  Amoebodont  and  An- 
tiodont  types  ;  as  an  example  of  the  former  kind  of  Bunodont, 
the  mandibular  molars  of  the  genus  Hyopsodus  may  be  cited  ;  of 
the  latter  kind,  the  same  of  the  genus  AchcBnodon,  both  the  ear- 
liest, or  Eocene  genera.     It  remains  to  indicate  the  intermediate 


MOLAE  TEETH   OF  THE  MAMMALIA  EDUCABILIA.     253 

forms,  if  any  there  be,  which  give  color  to  the  supposition  that 
the  various  divisions  of  Lophodonts  have  descended  from  Buno- 
dont  predecessors.  Here,  then,  I  mention  a  fact  of  prime  impor- 
tance, i.  e.,  that  in  America,  at  least,  no  Selenodonts  are  known 
from  formations  of  older  age  than  Miocene  ;  while  the  greatest 
development  of  Bunodonts  is  in  the  beds  of  the  next  older  epoch, 
the  Eocene. 

The  special  forms  of  Lophodonts  may  be  separately  considered 
as  follows  : 

First,  as  to  the  opposite  and  alternate  types,  or  the  Antiodont 
and  Amoebodont.  They  pass  into  each  other  by  many  intermedi- 
ate conditions  among  the  Bunodonts,  as  in  Notharchis,  Lim- 
notherium,  etc.,  of  the  Wyoming  Eocene.  There  is  reason,  also, 
to  believe  that  this  has  been  the  case  with  some  of  the  Lophodonts 
after  they  had  left  the  bunodont  stage  behind.  Thus  Equus  is  an 
antiodont  as  to  its  upper  molars,  but  has  been  probably  derived 
from  Palmotlieriodont  ancestors,  which  are  amoebodont ;  this  is 
rendered  especially  probable  by  the  fact  that  the  mandibular  teeth 
are  of  the  amoebodont  division  (hippodont).  It  is  also  highly 
probable  that  the  antiodont  genus  Tapirus,  though  so  near  to 
PalcBotlierhim,  was  derived  from  an  antiodont  Bunodont.  Hence, 
while  the  discrimination  between  opposite  and  alternate  types  is  in 
some  cases  most  radical,  in  others  its  importance  is  but  slight. 

L  Antiodonts:  Bunodont  type  AcTicenodon  (Fig.  19). 

1.  Selenodont  type  apjDroximated  by  the  bunodont  Hippopota- 
muSi  where  the  tubercles  are  com^^ressed,  thus  :  the  intervening 


Fig,  19. — AcTicenodon  insolens. 

valleys  are  deepened,  and  the  cusps  wear  readily  into  separate 
crescents.  Another  intermediate  form  is  seen  in  the  genus  An- 
tliracotherium,  where  the  tubercles  of  the  mandibular  teeth  are 
compressed,  while  they  remain  conic  (Fig.  21)  ;  selenodont  forms 
of  Omnivora  present  us  with  near  approaches  to  these  Bunodont 
genera.     Thus  in  Hyopotamiis  and  Anoplotheriiim,  the  crowns. 


254        THE   STRUCTURAL  EVIDENCE  OF  EYOLUTIOIT. 

when  unworn,  present  four  principal  tubercles,  wliicli  are  openly 
V-shaped  in  section,  and  which  are  separated  by  open  valleys. 

The  latter  are  deeper  than 
those  of  the  truly  Btmo- 
clont  genera,  but  much 
shallower  than  those  of  the 
typical  Selenodonts.  In 
Oreodon  the  valleys  are 
somewhat  deepened  and 
the  crescents  elevated,  while 
in  the  deer  the  same  infold- 
ing is  carried  still  further. 
In  the  Cavicornia  the  type 
reaches  its  fullest  expres- 
sion in  the  loss  of  the  shoul- 
der at  the  base  of  the  crown, 
the  great  elougation  of  the 
latter,  and  corresponding- 
ly deep  infolding  of  the 
terminal  valleys. 

Professor  Lartet*  states 
that  the  most  ancient  deer 
have  very  short  -  crowned 
molars,  and  the  depressions 
on  the  surface  are  so  shallow  that  the  bottom  is  always  visible, 
while  in  the  CervidcB  of   the  more  recent  Tertiary  periods,  and 

especially  the  Plistocene  and  living  species, 
these  same  cavities  are  so  deep  that  what- 


FiG.  20. — Hippopotamus. 


Fig.  21. — Hyopotamus  velaumis. 


Fig.  22. — ITyopotamus  americanus. 


Fig.  23. — Procamelns  robust  us. 


ever  be  the  state  of  attrition,  the  bottom  can  not  be  seen.  This, 
he  says,  is  a  perfectly  reliable  rule  for  distinguishing  the  ancient 
from  the  more  modern  forms  of  deer,  and  can  be  applied  to  other 
animals  as  well  as  the  CervidaB. 


*  u 


Comptes  Rendus,"  1868,  p.  1119. 


MOLAR   TEETH  OF  THE  MAMMALIA  EDUCABILIA.     255 


Fig.  24. — Merychyus  major. 


The  writer  nearly  contemporaneously  *  recalled  the  obserya- 
tions  of  Leidy  that  the  teeth  of  the  Oreodont  ^'  Merycliyus  are 
more  prismatic,  have  larger  crowns  atid  shorter  roots,  approaching 
the  sheep,  as  Oreodon  does  the  deer."  Now  Oreodon  is  Miocene, 
and  MerycJiyus  Pliocene.  It  was  then  ob- 
seryed  :  *'  This  phenomenon  suggests  an  ex- 
planation on  the  score  of  adajjtation  which 
the  other  cases  do  not.  The  existence  dur- 
ing the  later  period  of  a  [hardjer  material 
of  diet  would  increase  the  rapidity  of  wear- 
ing of  the  crown  of  the  tooth,  and  require  a 
longer  crown  and  greater  rapidity  of  j)rotru- 
sion.  This  necessitates  a  diminution  of  the 
basal  shoulder  and  shortening  of  the  roots,  producing  the  prismatic 
form  aforesaid." 

These  observations  render  it  highly  probable  that  the  seleno- 
dont  molar  is  produced  by  a  modification  of  the  antiodont  buno- 
dont  molar.  Also,  that  the  manner  of  the  change  has  been  by 
constant  acceleration  of  growth  of  the  folds  of  the  tooth  upward 
and  i^erhaps  downward  in  its  long  axis  ;  and  an  acceleration  in  the 
lengthening  of  the  crown. 

2.  Tapir odonts. — This  form  is  so  nearly  similar  to  the  Palaeo- 
theriodont  that  any  series  annectant  between  the  latter  and  the 
Bunodonts  will  render  very  probable  such  a  connection  for  the 
Tapirodonts  also.     Indeed,  it  is  clear  that  the  same  evidence  will 

be  sufficient  in  both  cases,  since  the  pre- 
molars and  last  molar  of  Lopliiodon  are 
amoebodont,  like  Palceotherium.  In  point 
of  fact,  however,  the  tubercles  of  the  molars 
of  Achcenodon  are  partly  united  in  transverse 
pairs,  while  there  are  intermediate  tubercles 
connecting  the  opposite  cones  in  some  molars 

of  Elotlierium.     These  structures  foreshadow  this  group  as  well 

as  the  Trichechodont. 

3.  Trichecodonts. — The  J[/«.«;^Of7o^5  and  Elephants  form  a  most 
complete  series  between  this  form  and  the  Bunodonts,  as  has  been 
pointed  out  by  Falconer.  In  this  series,  the  transverse  rows  or 
pairs  of  tubercles,  as  well  as  the  crests,  may  be  few  or  many.    Thus 


Fig.  25. —  Tapirus. 


*"  Proceedings  of  the  Academy  of  Natural  Sciences  of  Philadelphia,"  1868, 
p.  2Y4.     "  Origin  of  Genera,"  p.  44. 


256        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

in  Elotlierium,  HalWierium,  and   Tricliechus  they  are  few  ;  in 
Trachytherium  and  Dinotlierium  more  numerous  ;  in  Mastodon, 

Stegodon,  and  Elephas,  most 
numerous.  The  tubercles  are 
united  into  serrated  cross- 
crests  in  Halitherium,  the  ex- 
tinct sea-cow ;  in  Tracliytlie- 
rium,  another  fossil  ally  of  the 
Manati,  the  tubercles  are  not 
united.  The  succession  from 
Mastodon  to  Elephas  may  be 
represented  by  the  accompany- 
ing figures  :  Fig.  26  (from 
Cuvier)  is  a  molar  of  M.  an- 


FiG.  26. — Mastodon  angusHdens. 


gustidens,  where,  beside  the  principal  tubercles,  numerous  lesser 
ones  appear.     Fig.  27  represents  Mastodon  oMoticus,  in  which 


Fig.  27. — Mastodon  oMoticus. 


Fig.  28. — Dinotherium  giganteum. 


the  opposite  tubercles  are  nearly  united  into  transverse  crests. 
In  Dinotlierium  (Fig.  28)  and  Elephas  (Fig.  29)  the  union  is 
complete.  The  relation  of  these 
genera  has  been  described  as 
one  of  *'  inexact  parallelism"  ;  a 
condition  supposed  by  the  writer 
to  de23end  on  modification  in 
descent  under  the  law  of  acceler- 
ation. The  language  used  is  :* 
^*  The  young  tooth  of  Elephas, 
moreover,    is   represented    by   a 

»     .     n  T       ,  TT   1  Fig,  29. — Elephas  indicns. 

series    of    independent    parallel  ^ 

laminee  at  first,  which,  when  they  unite,  form  a  series  of  crests 


*  "Origin  of  Genera,"  p.  17. 


MOLAR  TEETH   OF  THE  MAMMALIA  EDUCABILIA.     257 


similar  to  the  type  [i.  e.,  pattern]  of  the  genus  Mastodon  [Stego- 
don\  and  others  of  the  beginning  of  the  series.     The  deposit  of 
cementum  takes  place  later,   till   the  valleys   are   entirely  filled 
up.    Thus  the  relations  of  this 
part  of  the  tooth  structure  in 
the  series  are  also  those  of  the 
cuccessional  growth  of  Elephas 
or  the  extreme  of  the  series." 
The    transition   from   the 


Fig.  30. — Microsyops  elegans. 


bunodont  type  to  the  lophodont  in  the  mandibular  dentition  is 
seen  in  the  Eocene  genera  Microsyops  and  Limnotlierium,  where 
the  opposite  cones  are  connected  by  a  low  cross-crest. 

n.  Amcebodonts;  Bunodont  type  ^^o/^.so(iws.* 

4.  Symlorodonts. — In  Hyopsodus  the  exterior  cones  are  already 
somewhat  excavated  on  the  inner  side,  so  that  a  section  of  each  is 
somewhat  triangular.  It  is  obvious  that  but  little  more  compres- 
sion and  curvature  are  required  to  produce  the  type  of  FalceosyopSf 


Fia.  31. — Eyopsodus. 


Fig.  33. — AncMppodus. 


Fig.  32. — PalcEOsyops  IcEvidens. 


Fig.  34. — Palceosyops. 


etc.  (Fig.  32).  The  angles  of  the  outer  cones  in  Hyopsodus  are 
also  slightly  produced  as  low  ridges  to  the  bases  of  the  alternating 
tubercles  of  the  opposite  side  :  the  elevation  of  these  ridges  is  only 

*  I  oridnallv  ("  On  the  Priinitive  Types  of  Mammalia  Educabilia,"  p.  9  ;  "  Hay- 
den's  Geolog.  Survey  Terr.,"  1872, 1873,  p.  648)  selected  Pliolophus  ( Oligotomus  Cope) 
for  this  position,  but  as  it  has  a  considerable  diastema,  it  is  better  exchanged  for 
Hyopsodus^  where  the  dental  series  is  uninterrupted. 
17 


258        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 


iiG.  35. — Falcjcotherlum. 


Fig.  36. — HipposTjus. 


necessary  to  produce  the  two  Vs  of  the  mandibular  dentition  of 
PcdcBotherium,  Palceosyops  (Fig.  34),  Symiorodon,  Anchippodus 
(Fig.  33),  and  all  their  allies  (Fig.  35,  PalcB other ium). 

5.  PcdcBotlieriodont  type.— Immediately  following  the  form  of 
the  Pcdceosyojjs  molar  we  have  that  of  Hipposyus,  where  inter- 
mediate tubercles  stand  be- 
tween the  inner  subconic  and 
the  exterior  longitudinal  cres- 
centoid  tubercles.  They  are 
compressed  so  as  to  be  trans- 
verse, and  only  need  more 
complete  connection  with  the 
adjacent  tubercles  to  give  the 
oblique  transverse  ridges  of 
A  ncliitheriiwi,  Palceotherium, 
and  Hyracodon,  Rlmiocerus, 
etc.  Hipposyus  was  origin- 
ally compared  with  Anchitherium  by  Dr.  Leidy,  and  the  writer  in 
ignorance  of  his  language  remarked  :*  "An  interesting  annectant 
form  is  seen  in  Lamhdotherium\  procyoiiinum,  where  the  two  inter- 
mediate tubercles  which  separate  the  inner  cones  from  the  outer 
Vs  in  Limnohyus  are  so  developed  as  to  constitute  parts  of  an  in- 
complete pair  of  transverse 
ridges  wiiich  disappear  in 
front  of  the  bases  of  the 
outer  Vs.  They  represent 
the  oblique  crests  of  Pcdmo- 
therium  and  A^ichitherium, 
and  thus  the  genus  Lamb- 
dothermm  furnishes  a  sta- 
tion on  the  line  from  Palce- 
osyops to  the  horses."  Contemporaneously  and  quite  independ- 
ently Prof.  Marsh  expressed  similar  views  X  as  to  its  affinities. 

A  greater  longitudinal  extent  of  these  ridges  or  longitudinal 
expansion  of  the  tubercles  in  the  molars  in  both  jaws,  the  oblique 
connections  being  still  retained,  gives  the  type  of  Equus  (Fig.  39). 
The  elevation  of  the  tubercles  and  deepening  of  the  valleys  gives 

*  Hayden's  "Geol.  Surv.  Montana,"  etc.,  1873,  p.  647. 

f  This  species  was  in  the  original  erroneously  called   Orohippus  procyonirvus, 
(Ed.  1886.) 

X  "Amer.  Joum.  Sci.  A>ts,"  1873,  p.  407. 


Fig.  37. — Hipposyus.        Fig.  38. — Ihjpoliippus. 


Fig.  39. 


MOLAR   TEETH   OF  THE  MAMMALIA  EDUOABILIA.     259 

us  the  Selenodont  type  of  superior  molars  again  in  this  genus  • 
while  the  lower  molars  only  differ  from  that  type  in  haying  the 
crescents  alternate  instead  of  opposite,  forming  the  Hippodont 
pattern  (Fig.  40).  There  can  be  little  doubt  that  the  line  of  the 
horses  comes  through  Hipp osij us*  from  the  Bunodonts,  rather  than 
through  Palceotherium,  as  has  been  sug- 
gested by  some  writers. 

6.  Bathmoclont  type. — I  know  of  no  ge- 
nus which  by  its  intermediate  structure 
connects  this  type  of  molar  with  the  Amoe- 
bodont  form  of  Bunodonts.f  Such  will 
doubtless  be  discovered,  for  it  is  impossible 
that  the  upper  molar  of  Bathmodon  could 
have  been  produced  by  the  modification  of 
any  known  PalsGotheriodont,  the  type  which 
it  most  nearly  resembles.  The  structure  of 
the  feet  of  the  animal  forbids  any  such  sup- 
position. Such  intermediate  tyj^es  would 
have,  firstly,  the  (oblique)  crests  more  nearly 
equal  in  length  and  similar  in  direction.  A 
depression  of  the  crests  and  indication  of 
diagonal  ridges  connecting  the  tubercles  in 
the  opposite  direction  would  produce  an 
approach  to  a  W,  and  the  form  of  Hyopso- 
dus.  That  this  was  probably  the  history 
of  this  curious  type  is  rendered  probable  by 
the  form  of  the  mandibular  teeth,  which  exhibit  two  of  the  in- 
termediate stages  above  anticipated.  Thus  the  last  inferior  molar 
exhibits  two  obliquely  transverse  crests  of  subequal  length,  with 
rudimental  oblique  or  diagonal  ridges  connecting  them.  In  the 
median  lower  molai's  one  of  the  latter  is  developed,  giving  a  V, 
as  in  PalcBotherium,  but  the  posterior  one  is  undeveloped,  leaving 
only  the  original  oblique  cross- crest.  J 

7.  The  Loxolophodonts. — Like  the  preceding  group  I  know 
of  no  type  connecting  this  form  with  the  Bunodont,  but  antici- 
pate the  discovery  of  a  type  with,  a  rudimental  posterior  V  on  the 


Superior  molar  of 
Equus, 


Fig.  40. — Inferior  molar  of 

Equus. 


*  I  have  since  shown  that  Hyracotherium  and  Pliolophus,  which  have  very 
similar  dentition,  are  the  types  which  occupy  this  position.     (Ed.  1886.) 

•f  Such  has  since  been  discovered  in  the  genus  Pantolambda  (Cope).    (Ed.  1886). 

X  See  "  Proceed.  Amer.  Philosophical  Society,"  Sept.,  1872,  "  On  the  Dentition  of 
Metalophodony 


260        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

upper  molars,*  which  shall  connect  it  with  the  W-shaped  type 
proposed  above  as  the  probable  predecessor  of  Bathmodon.  Or,  a 
pair  of  oblique  parallel  crests  with  rudimental  diagonals  like  the 
posterior  lower  molars  of  Bathmodon  may  intervene  between  this 
form  and  the  Bunodont.     This  is,  however,  not  probable  in  view 


Fig.  41. — Bathmodon. 


of  the  diagonal  crest  of  the  upper  molars  (Fig.  42,  Uintatlierium 
robustum),  and  especially  if  the  parallel  with  the  type  of  the 
lower  molars  is  kept  up.     These  are  like  those  of  Bathmodon,  ex- 


Figs.  42  and  43. —  Uintatherium  rohustum. 

cept  that  the  type  of  the  middle  molars  of  the  latter  is  continued 
to  the  posterior  end  of  the  series  in  Uintatherium  (Fig.  43)  ;  that 
is,  the  last  molar  of  the  latter  consists  of  a  V  and  an  oblique  cross- 
crest. 

Y.    RELATIOKS   OF   THE   TYPES   OF    DEI^TITIOI^'    TO    TYPES    OF    FOOT 

STEUCTURE . 

I  hope  that  I  have  succeeded  in  showing  that  the  Bunodont 
and  Lophodont  types  of  dentition  form  two  homologous  series, 

*  This  has  since  been  discovered  in  Pantolambda  (Cope).     (Ed.  1886.) 


MOLAR   TEETH   OF  THE  MAMMALIA  EDUCABILIA.     261 

similar  to  those  already  indicated  among  BatracMa,  Anura,  CepJi- 
alopoda,  etc.*  That  this  relation  indicates  descent  of  the  corre- 
sponding terms  of  the  one  series  from  those  of  the  other  has  also 
been  rendered  highly  probable.  This  conclusion  has  also  been 
previously  stated  as  a  theorem,  f  as  follows  :  ^'  V*  The  heterologous 
terms  or  genera  in  the  later  series  are  modified  descendants  of  those 
of  the  earlier  series  "  ;  in  other  words,  that  certain  groups  higher 
than  genera  are  produced  from  others  of  a  similar  high  value  by 
*^  descent  with  modification." 

As  already  pointed  out,  the  Bunodont  primary  genera  belong  to 
the  older  geologic  epoch  of  the  Eocene,  while  most  of  the  deriva- 
tive ones  belong  to  later  periods.  Some  were  contemporary  with 
the  primary  forms,  but  doubtless  have  descended  from  pre-existent 
members  of  the  same  type  as  yet  unknown  to  us.  The  genus 
Achmnoclon,  Cope,  is  especially  generalized  in  three  respects  :  (1) 
the  simplicity  of  the  construction  of  its  molars  ;  (2)  the  same 
simplicity  of  the  premolars,  which  are  without  inner  or  posterior 
lobes ;  (8)  the  absence  of  all  diastemata  and  consequent  continu- 
ity of  the  dental  series.  Hence  it  maybe  regarded  as  more  primi- 
tive than  PalcBOchcerus,  Cheer omor us,  Dicotyles,  or  Elotlierium, 
in  all  which  there  are  marked  diastemata.  The  two  series  may  then 
be  arranged  as  follows  :  with  the  understanding  that  in  some  cases 
names  of  genera  used  represent  rather  family  groups,  in  which 
the  special  generic  lines  have  not  yet  been  made  out.| 

The  following  table  has  been  already  published  in  its  essential 
features  in  the  ^*  Report  on  Geological  Survey  of  the  Territories," 
1873,  p.  648.* 

It  remains  now  to  ascertain  whether  the  genealogical  or  taxo- 
nomic  relations  expressed  by  the  teeth  coincide  with  those  derived 
from  the  other  diagnostic  regions  of  the  body.  First  of  these  must 
be  selected,  as  of  chief  importance,  the  limbs  and  feet. 


*  See  "  Origin  of  Genera,"  p.  53.  t  Lo<^-  ^«^-  P-  '^9. 

X  Since  the  following  table  was  published  it  has  become  probable  that  Achaeno- 
don  is  an  unguiculate  and  a  flesh-eater.  It  has  also  been  discovered  that  the  genus 
Phenacodus  possesses  the  characters  which  give  it  the  place  as  the  ancestor  of  all 
the  lines  in  the  table.     (Ed.  1886.) 

#  It  was  previously  published  in  a  separate  form  in  "  On  the  Primitive  Types  of 
Mammalia  Educabilia,"  May  6, 1SY3.  An  error  occurs  in  this  edition  in  the  reversal 
by  a  lapsus  calami  of  the  positions  of  the  types  Omnivora  and  Anoplothcrium.  It 
is  also  important  to  note,  that  in  the  "  Report  G.  S.,"  p.  645,  where  it  is  stated  that 
"  during  the  Eocene  they  (the  orders)  were  in  process  of  difPerentiation,"  etc.,  Mam- 
malia Educabilia  and  not  Zissencephala,  are  referred  to. 


262        THE  STRUCTURAL  EVIDENCE  OF  EVOLUTION. 


o 

o 


o 

CO 


r^_ 


13:1 


52: 
O 

Q 
O 


8 

o 


o 

•to 


^ 


o 


o 

a. 

// 


s 


=0 


O 


Loxolophodont 


Bathmodont 


=0 

o  — 


CO 

o  - 

.1 


.1 


^ 


Symborodont 
Palseotheriodont 
Selenodont  pt. 


-8 


_    P   _ 

O 

■5. 


to 


e 


OS 
O 


_  o 


09 


Trichechodont 


8 
•50 


-  o  - 

t 


o 


60 


CO 

O 


I- 


Tapirodont 


—  %  —  h  — -o        Selenodont 


6 


00 


O 


-Y- 


o 

O 


o 

O 

o 


MOLAR   TEETH  OF   THE   MAMMALIA  EDUCABILIA.    263 

We  may  look  on  the  Artiodadyla — even-toed  or  cloven- footed 
mammals — as  one  of  the  most  homogeneous  groups  in  the  class, 
not  only  in  respect  to  the  structure  of  the  extremities,  but  also  in 
that  of  the  cranium,  vertebrae,  etc.  But  here  we  have  both  Buno- 
dont  and  Selenodont  types  of  molars.  The  Perissodactyla,  as  de- 
fined by  the  feet,  axis,  palate,  etc.,  present  us  with  the  Symhoro- 
dont,  PcdcBotheriodont,  Tapirodont,  and  Selenodont  types  of  denti- 
tion in  the  superior  series,  and  the  Hippodont,  Hyracodont,  Pa- 
IcBotheriodont,  and  Trichecliodont  types  in  the  mandibular  teeth. 
The  pentadactyle,  plantigrade  type,  for  which  I  have  used  the 
name  Proboscidia,  presents  us  with  the  Trichecliodont,  Bathmo- 
dont,  and  Loxolophodont  types  of  molar  structure.  Among  Siren- 
ians,  as  defined  by  the  marked  peculiarities  of  the  entire  skeleton, 
we  have  the  great  differences  in  dentition  presented  by  Halicore 
and  Trichecus,  the  former  being  Haplodont,  the  other  TrichecJio- 
dont.  Finally,  the  Marsupial  group  is  unquestionably  well  defined, 
and  here  Pliascolomys  is  Ptycliodont ;  Didelphys,  Bunodont  j  Pe- 
taiirus  between  Bunodont  and  Selenodont,  and  the  Kangaroos  and 
their  gigantic  extinct  allies  the  Diprotodontidce,  Trichecliodont. 

It  is  thus  evident  that  the  molar  types  are  everywhere  subor- 
dinated to  those  which  we  call  ordinal ;  therefore  in  the  case  of 
the  placental  mammals,  and  especially  those  with  complex  folding 
of  the  cerebral  hemispheres,  to  the  types  of  construction  of  the 
feet.  As  to  the  modifications  presented  by  the  canine  and  incisor 
teeth,  these  exist  within  a  still  more  narrow  range  of  variation  ; 
for  instance,  in  the  allied  genera  Equus,  Rhinaster,  and  Symhoro- 
don  ;  Sus  and  Phacochwrus  ;  Bathmodon  and  Unitatherium,  and 
others. 

It  is  thus  probable  that  modifications  in  the  three  points  of 
structure  considered  were  introduced  in  the  following  order : 

First,  Of  the  feet. 

Second,  Of  molar  type.* 

Third,  of  the  relations  of  canines  and  incisors. 

With  regard  to  the  significance  of  the  tnree  types  of  feet,  Pro- 
hoscidian,  Perissodactyle,  and  Artiodactyle,  it  has  been  already 
remarked:    ^'It  is  to  be  observed  that  the  lines  of   Ungulata, 


*  In  the  case  of  the  Marsupialia  the  relation  of  the  dental  and  extremital  types 
may  be  reversed.  Thus  we  have  pentadactyle  plantigrade  forms  (Opossums)  and 
(nearly)  didactyle  digitigrade  forms  {Macropus)  in  the  same  order.  Also  Hahnatu- 
rus  and  Diprotodon,  both  Trichechodonts,  differ  in  the  type  of  feet,  as  do  the  car- 
nivorous Didelphys  and  Thylacinus,  both  Bunodonts. 


264        THE   STRUCTUEAL  EVIDENCE   OF  EVOLUTION. 

Quadrumana,  and  Carnivora  originate  in  plantigrade  types,  a 
state  of  things  quite  predominant  among  the  lower  series  or  Lis- 
sencephala  (smooth  brains).  It  is  universal  in  Edentata  and  very 
usual  in  Rode7itia  and  Insectivora.  The  lower  forms  of  Marsu- 
pialia  and  all  of  the  Monotremes  present  it.  In  the  Marsupials, 
Rodents,  Ungulates,  and  Carnivores,  we  have  series  whose  highest 
expression  is  in  the  most  highly  digitigrade  genera."*  To  this  it 
may  be  added  that  the  lower  terrestrial  vertebrates  are  plantigrade, 
with  some  exceptions.  Thus  in  some  Anurous  BatracMa  there  is 
a  partial  digitigradism  ;  the  only  digitigrade  Reptilia  are  some 
Dinosauria,  especially  such  carnivorous  forms  as  Lcelaps ;  all 
birds  are  digitigrade.  The  digitigrade  modification  evidently  has 
reference  to  speed  in  running,  or  projectile  force  in  leaping. 

The  connecting  points  between  the  different  types  of  foot- 
structure  among  the  Ma7nmalia  Educahilia  are  as  obvious  as  in 
the  case  of  the  types  of  molar  structure.  Examples  may  be  ad- 
duced as  follows  : 

Carnivora. — In  all  of  the  genera  of  the  Eocene  Carnivora  which 
I  have  had  the  opportunity  of  examining,  excepting  3Iesonyx, 
namely,  Amhlyctonus,  Oxycena,  Prototomus,  Didymictis,  the  tibio- 
astragalar  articulation  is  of  a  primitive  character.  The  astragalus 
is  flat,  and  the  applied  surfaces  are  nearly  a  plane,  and  without 
the  pulley-shaped  character  seen  in  existing  Carnivora ;  as  dogs, 
cats,  and  in  a  less  degree  in  the  bears  and  in  other  Mammalia  with 
specialized  extremities,  as  Perissodactyla,  Artiodactyla,  etc.  The 
simplicity  of  structure  resembles,  on  the  other  hand,  that  found 
in  the  opossum  and  various  Insectivora,  Rodentia,  and  Quadru- 
mana, and  in  the  Proioscidia,  most  of  which  have  the  generalized 
type  of  feet.  The  structure  indicates  that  the  carnivorous  genera 
named  were  plantigrade — a  conclusion  which  is  in  conformity 
with  the  belief  already  expressed  that  the  Mammalia  of  the  Eocene 
exhibit  much  less  marked  ordinal  distinction  than  do  those  of  the 
Miocene  or  the  recent  periods.  It  is,  indeed,  questionable  whether 
some  of  the  genera  here  included  in  the  Carnivora  are  not  gigantic 
Insectivora,  since  the  tibio-tarsal  articulation  in  many,  the  separa- 
tion of  the  scaphoid  and  lunar  bones  in  Mesonyx,  the  form  of  the 
molars,  and  the  absence  of  incisor  teeth  in  some,  are  all  character- 
istic of  the  latter  rather  than  the  former  order. 

Artiodactyla. — Approximations  to  the  Perissodactyla  are  to  be 

*" Mammalia  Educabilia,"  p.  8;  Hayden's  "Geological  Survey,"  18Y3,  p.  647. 


MOLAR  TEETH   OF  THE   MAMMALIA  EDUOABILIA.     265 

seen  in  Hippopotamus  in  the  increase  in  development  of  the  lat- 
eral or  first  and  fourth  digits,  thus  equaling  the  number  in  the 
fore-foot  of  Tapirus  and  Menodus,  though  preserving  the  equal- 
ity of  the  two  median  digits.  But  an  inequality  of  these  digits 
appears  in  the  genera  Anoplotherium  and  Cmnotlierium,  as  has 
been  stated^  in  the  following  language  :  '^In  Anoplotherium  se- 
cundarium  the  digit  ii  is  developed  in  each  foot,  though  not 
nearly  so  long  as  m,  which  is  nearly  symmetrical  in  itself.  There 
is  an  approach  to  the  same  structure  in  the  manus  of  Cmnotlie- 
rium.^^  The  only  approximation  to  the  Proboscidian  type  is  to  be 
seen  in  the  shortening  of  the  metapodial  bones  in  Hiiopopotamus, 
a  point  of  very  inconsiderable  value. 

Perissodadyla. — Approximation  to  the  preceding  order  is 
made  in  the  anterior  foot  of  Menodus,  in  which,  according  to 
Marsh,  there  are  four  toes  of  nearly  equal  size,  f  Apj^roximation 
to  the  Proboscidia  X  is  seen  in  Symtorodon,  where  the  cuboid  facet 
of  the  astragalus  is  rather  larger  than  in  Rhinoceros,  and  devel- 
oped much  as  in  Bathmodon ;  the  small  third  trochanter  of  the 
femur  is  also  much  like  that  in  Bathmodon.  The  osseous  horn- 
cores  may  be  compared  with  those  on  the  front  of  Loxolophodon. 
The  knee  was  probably  free  from  the  integument  of  the  abdomen, 
as  in  Proboscidians,  In  all  other  respects  there  is  no  approxima- 
tion to  this  order. 

Proboscidia.  —  The  approximations  to  other  orders  in  the 
structure  of  the  feet  are  only  to  be  seen  in  the  Eocene  genera 
Bathmodon  and  Eohasileus.  The  latter,  or  its  ally  JJiyitatherium, 
presents,  according  to  Marsh,  but  four  toes  on  the  hind  foot ;  the 
anterior  has  five.  In  the  former  point  we  have  a  resemblance  to 
Hippopotamus,  but  one  of  little  significance,  in  view  of  the  radical 
differences  between  the  two  in  the  form  of  the  astragalus,  cal- 
caneum,  and  cuboid  bones.  The  former  is  essentially  Proboscidian 
in  all  respects,  with  the  addition  of  a  cuboid  facet  alongside  of 
and  behind  the  navicular,  as  in  Symhorodon  ;  thus  constituting  a 
Perissodactyle  character,  but  leaning  to  the  forms  of  that  order 
which  betray  probably  the  closest,  though  slight,  approach  to  the 
omnivorous  division  of  the  Artiodactyla.  Thus,  while  the  Uinta- 
theriidcB  present  the  Proboscidian  type  of  feet  and  molar  dentition, 

*  Huxley,  "Anatomy  of  the  Vertebrated  Animals,"  p.  321. 
f  "American  Journal  of  Science  and  Arts,"  1873,  p.  486. 

i  This  should  be  Amblypoda,  not  separated  from  the  Proboscidia  at  the  time 
this  was  written.     (Ed.  1886.) 


266        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

if  they  present  any  ordinal  characters  resembling  those  of  the 
Artiodactyla,  they  are  equally  shared  by  certain  extinct  Perisso- 
dactyla. 

From  the  hints  above  furnished,  we  may  regard  the  succession 
of  modifications  of  foot-structure  to  be  nearly  as  follows  ; 

Ruminantia.  Rhinocerus.  Equus.  Elephas. 

Omnivora.  Palseotheriura.        Hyracotherium.* 

\  /  / 

\  /  / 

Sjinborodoa.         Palseosyops.  Uintatherium. 

\  /  / 

\        /  / 

\     /  / 

x/  / 

,  *  Bathmodon. 

\  / 

\v  // 

\         / 

\     / 

\/ 

* 

VI.    THE   ANCESTRAL  TYPE   OF   MAMMALIA   EDUCABILIA. 

I  trust  that  I  have  made  it  sufficiently  obvious  that  the  primi- 
tive genera  of  this  division  of  mammals  must  have  been  Buno- 
donts  with  pentad actyle  plantigrade  feet.  It  therefore  follows  that 
Eleplias  was  not  the  descendant  of  Eoiasileus  nor  Bathmodon  in 
a  direct  line,  but  from  some  common  ancestor  with  tubercular 
teeth,  through  Mastodon.  We  may  anticipate  the  discovery  of 
such  a  genus,  and  believe  that  it  will  not  be  widely  removed  from 
the  Eocene  Hyopsodus,  or  perhaps  Achcenodon.  This  will,  then, 
be  the  primitive  ungulate. 

But  it  will  be  more  than  this  ;  it  can  not  be  far  removed  from 
the  primitive  carnivore  and  the  primitive  quadrumane.  The  Car- 
nivora  are  all  modified  bunodonts,  and  the  lower  forms  ( Ursus 
Procyon,  e.  g.)  are  pentadactyle  and  plantigrade.  As  to  the 
Quadrumana,  man  himself  is  a  pentadactyle  plantigrade  buno- 
dont.  This  view  has  been  already  expressed,  as  follows:  '^^The 
type  of  Tomitlierium,  already  described,  evidently  stands  between 
lemurine  monkeys  and  such  small  allies  of  Palmotlieriidm  with 
conic  tubercular  teeth  {Oligotomus,  OrotJierium,\  etc.),  and  which 
abound  in  the  Eocenes  of  Wyoming.  .  .  .  The  dentition  of  the 
two  types  is,  indeed,  but  little  different  in  the  Quadrumanous  and 

*  This  was  called  Hipposyus  in  the  original  essay — a  name  which  really  applies 
to  a  different  type.     (Ed.  1886.) 

t  Both  these  are  names  for  Pliolophus,  a  close  allay  of  Ilyracotherium.     (Ed. 

1886.) 


MOLAR   TEETH   OF   THE   MAMMALIA  EDUCABILIA.     267 

Ungulate  types  respectively,  being  a  continuous  series  of  I.  1  or 
2  ;  C.  1  ;  P.  m.  3 — 4  ;  M.  3  ;  the  canines  but  moderately  devel- 
oped. "*  Such  a  hypothetical  type  might  be  expressed  by  the 
name  BunotlieriidcB,  with  the  expectation  that  it  will  present  sub- 
ordinate variations  in  premolar,  canine,  and  incisor  teeth.  The 
premolars  might  be  expected  to  differ  in  the  degree  of  development 
of  the  internal  lobes,  the  canine  in  its  proportions,  and  the  incisors 
in  their  number. 

In  respect  to  the  limbs  proper,  neither  the  Quadriimana  nor 
Carnivora  attain  to  the  specialization  seen  in  the  Artiodactyla 
and  Perissodadyla,  for  the  ulna  and  fibula  are  never  atrophied 
nor  co-ossified  with  the  radius  and  tibia,  but  are  always  distinct 
and  free  ;  the  only  modification  of  structure  in  these  points  being 
the  slight  one  involved  in  developing  the  rotary  capacity  seen  in 
the  higher  monkeys. 

Thus  the  human  series  preserves  in  its  feet,  limbs,  and  den- 
tition, more  of  the  characteristics  of  the  primitive  Bunotlieriwn 
than  any  other  line  of  descent  of  the  Mammalia  EducaMlia.  It 
even  exhibits  a  retrogression,  in  the  transition  from  the  anisog- 
nathous  Tomitherium  to  the  genus  Homo,  where  the  teeth  in  the 
two  jaws  are  exactly  alike,  as  well  as  in  the  resumption  of  the 
continuity  of  the  dental  series  after  the  diastema  had  prevailed 
among  the  higher  monkeys.  In  one  respect  it  has  steadily  ad- 
vanced, viz.,  in  the  number  of  convolutions  and  extent  of  the 
cerebral  hemispheres  and  relative  size  of  the  brain  as  a  whole. 

Note  (Ed.  188fi). — As  remarked  in  a  previous  note,  the  discovery  of  the  general 
characters  of  the  genus  Phenacodus  in  1881,  more  than  six  years  after  the  publica- 
tion of  this  paper,  demonstrated  the  truth  of  the  hypothesis  here  proposed,  viz. : 
that  the  ancestor  of  the  Mammalia  Educabilia  was  a  pentadactyle  plantigrade  buno- 
dont.  The  numerous  genera  and  species  allied  to  Phenacodus  have  been  placed  in 
a  suborder  Condylarthra.  See  "  American  Naturalist,"  1884,  790,  for  an  illustrated 
article  on  this  group. 


* 


Ilayden's  "  Geological  Survey  of  Montana,"  etc.,  1872,  p.  645. 


VIII. 


THE  EELATION   OF  MAN  TO   THE   TERTIARY 

MAMMALIA.* 

Ii^"  order  to  prove  the  affirmative  of  a  doctrine  of  evolution  by 
descent  of  the  existing  types  of  living  beings,  two  propositions 

must  be  established.  The  first, 
that  a  relation  of  orderly  succes- 
sion of  structure  exists,  which 
corresponds  with  a  succession  in 
time.  Second,  that  the  terms 
(species,  genus,  etc.)  of  this  suc- 
cession actually  display  transitions 
or  connection  by  intermediate 
forms,  whether  observed  to  arise 
in  descent,  or  to  be  of  such  vari- 

Fia.  AA.-Periptychm  rhabdodon   part    ^^^^    character  aS    to   admit  of  nO 
of  posterior  foot,  two  thirds  natural  size ;  •  ^     i     •  •    • 

b,  astragalus  from  above,  showing  flat  other  explanation  of  their  origin 

face;  e,  metatarsals,  the  first  lost,  show-    than  that  of  deSCCnt.. 

ing  plantigrade  foot.       Original;   from  j^  ^|-^g  g^i^j  ^f  paleontology  it 

Puerco  Epoch  of  New  Mexico.  .  .,  -i  i       j        t  7     i 

IS  quite  possible  to  demonstrate 
the  first  of  these  propositions,  while  the  proof  of  the  second  is 
necessarily  restricted  to  the  observation  of  variations  and  the  dis- 
covery of  connecting  forms  which  destroy  the  supposed  definitions 
of  species,  genera,  etc.  The  conditions  are  more  favorable  for  the 
investigation  of  animals  of  the  higher  types  than  of  those  of  the 
lower.  Their  late  origin  insures  to  us  the  opportunity  of  discovery 
of  their  ancestry  far  more  certainly  than  in  the  case  of  the  lower, 
whose  beginnings  are  lost  in  the  remote  past,  and  belong  to  periods 
whose  deposits  have  undergone  physical  changes,  or  have  been  en- 
tirely removed  and  redeposited  elsewhere,  thus  insuring  the  de- 
struction of  the  fossil  remains  once  contained  in  them.  The  series 
of  the  tertiary  Mammalia  is  becoming  more  complete  through  the 

*  Read  before  the  American  Association  for  the  Advancement  of  Science,  at 
Detroit,  1875,  under  another  title. 


EELATION"  OF  MAN  TO   THE  TERTIARY  MAMMALIA. 


269 


Fig.  45. — Caryphodon  elepJiantopiLS^  anterior 
foot  from  above,  one  third  natural  size.  From 
Lower  Eocene  of  New  Mexico.  The  cuneiform 
{Cu)  is  injured.     (Original.) 


recent  explorations  in  the  West,  and  the  results  are  embraced  in 

the    forthcoming    quarto 

reports  of  the  Hayden  and  z^^^fc^^'^K^S'c 

Wheeler  U.  S.  Geological,  Cu 

etc.,  surveys  of  the  Terri-         ^'n- 

tories.       An    abstract    of 

some  of  these  is  given  in 

the  present  essay. 

The  primary  forms  of 
the  Mammalia  repose  in 
great  measure  on  the  struc- 
ture of  the  feet.  Those  of 
the  teeth  are  also  very  sig- 
nificant, but  present  a 
greater  number  of  varia- 
tions among  animals  other- 
wise nearly  related.  The 
osteology  of  the  feet  of  re- 
cent land  mammals  falls  into  several  categories.     These  may  be 

called  the  plantigrade, 
many-toed  type  ;  the  car- 
nivorous type  ;  the  horse 
type,  and  the  ruminant 
(e.  g.,  ox)  type.  The 
lower  vertebrates,  as  sala- 
manders, lizards,  etc.,  dis- 
play the  simplest  form  of 
feet,  having  usually  five 
toes,  with  numerous  sepa- 
rate bones  of  the  palm 
and  the  sole,  which  they 
apply  to  the  ground  in 
progression.  The  many- 
toed  or  multidigitate 
type  of  mammalian  foot 
most  nearly  resembles 
this  condition,   but    dif- 

FiG.  46.— Posterior  foot  of  CorypTiodon  elephan-    fers  in   the  points  of  dif- 
topus.   From  Lower  Eocene  of  New  Mexico.   (Orig-    f  p^'ence    which    are    Com- 
mon   to    all    Mammalia. 
In  the  hind  foot  a  succession  of  forms  leads  from  this  general- 


270        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTIOK 


ized  type  to  the  extreme  specializations  observed  in  the  horse  and 
the  ox. 

The  modifications  are  as  follows  :  The  hind  foot  is  composed 
of  two  rows  of  tarsal  bones,  of  which  the  second  is  followed  by 
the  long  metatarsal  bones,  from  which  the  bones  of  the  toes  origi- 
nate. The  second  segment  of  the  hind  leg  is  composed  of  two 
boues,  tibia  and  fibula,  which  in  the  salamander,  etc.,  have  a  sub- 
equal  union  with  the  foot.  In  some  multidigitates,  as  the  genus 
Corypliodon,  both  these  bones  articulate  with  the 
two  bones  of  the  first  row  of  the  tarsus,  and  one 
(fibula)  is  the  smaller  of  the  two.  In  many  higher 
forms  they  articulate  with  but  one  of  these  tar- 
sal bones,  viz.,  the  astragalus,  with  which  they 
form  a  perfect  hinge  joint ;  the  other  tarsal  bone 
of  the  first  row  is  the 
calcaneum  or  heel-bone. 
In  Coryjjliodon  the  as- 
tragalus and  the  applied 
leg-bone  (tibia)  are  near- 
ly flat,  offering  an  ex- 
tremely imperfect  hinge 
for  the  foot,  and  the 
heel-bone  (calcaneum) 
is  exceedingly  short. 
The  animal  plainly 
walked  on  the  entire 
sole  of  the  foot,  and 
must  have  had  an  awk- 
ward gait,  from  the  Fig.  47.— Left  anterior 
slio'ht  power  of   flexins^    ^ooX.oi  Phenacodus  primal-    foot  of  PTienacodusprimos,- 

the  ankle-joint.  From  ""''^^"^- '^''- ^^"^^-^  t^^«,  K  nat.  size.  (Orig.) 
this  point  to  the  horse  on  one  side,  and  to  the  ox  on  the  other,  we 
have  a  line  of  succession  of  intermediate  forms.  And  before  de- 
scribing them,  I  may  state  that  the  Corypliodon  is  one  of  the  old- 
est known  Mammalia,  its  remains  having  been  found  in  the  Lower 
Eocene  Tertiary  of  New  Mexico  and  Wyoming,  while  the  ox  and 
horse  are  extremely  modern  animals,  their  advent  on  the  earth 
having  preceded  that  of  man  by  but  one  geological  period. 

The  most  perfect  ankle-joint  is  that  of  the  ruminating  animals. 
The  astragalus  presents  a  deeply  grooved  segment  of  a  pulley  ;  an 
angulated  pulley,  face  downward  to  the  rest  of  the  foot,  and  a 


Fig.  48. — Left  posterior 


PLATE   VI. 


272        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 


smooth  convexity  to  the  hollow  of  the  applied  heel-bone  behind. 
No  such  astragalus  has  ever  been  found  in  the  Lower  Eocene  forma- 
tions of  America  ;  animals  bearing  it  in  a  less  perfect  stage  appear 
in  the  next  higher  period,  the  Miocene  ;  but  it  is  not  until  the 
Pliocene  and  modern  times  that  they  abound.  In  the  Hipjwpota- 
mus  foot,  we  have  an  example  of  the  less  perfect  astragalus  of  this 
type  of  animals.  The  pulley  surfaces 
are  flatter  and  less  deeply  grooved. 

In   the   horse,  the  upper  surface 
of   the   astragalus   forms  as   perfect 


>7mrve  /irfaulan 

POLLICIS 


Cfjrpi'S 


eJT. CARPI  ULNAR  IS 


pni»M 
RNoan 


nir</f» 


EXT.  COWMUNIS 
DICITORUM 
EKI.INOICIS 


EXT   COMMUNIS 
DlGlTOPtM 


Fig.  49. — Anterior  foot  of  Homo  sapiens  from 
above,  one  tliird  natural  size.  From  Allen's 
Anatomy. 


Omnvf  /tff 

(>ER0NELIS1,0NCUS 

Oroox-t*  for 
PONEUS  BPEVIS 

3liicn:/e/ororoyiit  o^ 
AS:  OIN.  Die. 


Fig.  50. — Posterior  foot  of  do. 
from  above,  one  third  natural 
size.     From  Allen's  Anatomy. 


a  joint  as  in  ruminants,  but  the  lower  and  hinder  faces  present 
the  flattened  surfaces  which  belong  to  the  many-toed  Mammalia. 
The  lower  face  especially  is  mainly  occupied  by  one  large  facet,  in- 
stead of  the  two-faced  pulley  of  the  ruminants.  In  the  rhinoceros 
a  later  facet  is  more  distinct,  while  in  the  Miocene  Menodus  the 
second  facet  is  larger,  resembling,  except  in  the  still  convex  tibial 
articulation,  the  structure  of  that  of  the  primitive  Corypliodon. 


RELATION   OF  MAN"  TO   THE   TERTIARY   MAMMALIA.     273 


In  the  heel-bone  we  have  a  succession  from  the  short  and  flat 
form  of  Coryphodon  to  the  long  and  slender  one  of  the  horse  and 
ruminants  ;  the  increase  in  length  being  associated  with  the  elon- 
gation of  the  bones  of  the  toes,  and  the  assumption  of  the  digiti- 
grade  type  from  the  planti- 
grade. The  mammals  of  the 
Lower  Eocene*  exhibit  a 
greater  percentage  of  types 
that  walk  on  the  entire  sole 
of  the  foot,  while  the  suc- 
ceeding periods  exhibit  an 
increasing  number  of  those 
that  walk  on  the  toes,  while 
the  hoofed  animals  and  Car- 
nivora  of  recent  times  nearly 
all  have  the  heel  high  in  the 
air,  the  principal  exceptions 
being  the  elephant  and  the 
bear  families. 

A  most  noticeable  succes- 
sion is  seen  in  the  diminu- 
tion of  the  number  of  toes. 
In  the  series  leading  to  the 
horse,  the  ox,  and  the  hyaena 
and  cat,  this  reduction  pro- 
ceeds by  the  loss  of  a  toe 
from  the  one  side  or  the 
other,  until  in  the  ruminants 
but  two  are  left,  and  in  the 
horse  but  one.  The  series  ex- 
tending from  the  primitive 
Eocene  types  with  five  digits, 
to  the  existing  reduced  forms, 

is   most    complete,     although  Fig.  b\.—Phenacodus  primcevus  skull,  one 

a  few   of    the    New    Mexican    third  natural  si^e,  from  below,  showing  quadri- 
-c^  ,1  1  tubercular  true  molars.    From  specimen  figured 

Eocene     genera     themselves         ,  .  r  & 

^  _  on  plate. 

probably    exhibit    but    four 

digits  on  one  or  both  pairs  of  feet.     The  presence  of  the  rudiments 


*  All  the  Mammalia  of  the  Puerco  fauna  (which  was  unknown  at  the  time  this 
lecture  was  delivered)  are  plantigrade.     (Ed.  1886.) 


18 


274        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

of  the  lost  lateral  digits  is  constantly  observed,  and  when  these 
disappear  it  is  to  be  finally  replaced  by  the  rudiments  of  the  ad- 
joining toes  in  i^rocess  of  similar  reduction.  The  bones  of  the  sec- 
ond row  of  the  tarsus  which  are  in  connection  with  the  toes  are 
not  reduced  so  rapidly  as  the  toes  themselves;  hence,  the  bones  of 
the  toes,  in  order  to  maintain  the  fit  of  the  i^arts,  increase  in 
width,  and  consequently  in  strength.  As  is  well  known,  in  the 
horse  the  single  toe  is  as  stout  as  several  united  toes  of  lower 
forms,  and  the  two  toes  of  the  ruminants  have  their  basal  seg- 
ments (metatarsals)  united  into  a  stout  solid  mass,  the  cannon- 
bone.  At  the  same  time  several  of  the  small  bones  of  the  sec- 
ond tarsal  row  become  coossified,  so  that  we  have,  in  the  rumi- 
nants and  horse,  the  greatest  consolidation  of  structure,  connected 
in  the  former  with  the  most  elegant  mechanism.  It  is  scarcely 
necessary  to  add  that,  in  the  various  cases  of  coossification  and 
consolidation  described,  the  foetus  displays  the  original  elements 
separated. 

In  the  fore  limb  the  same  successional  reduction  in  the  number 
of  toes  may  be  traced  as  I  have  described  in  the  hind  foot ;  but, 
as  the  bones  of  the  palm  differ  from  those  of  the  sole,  the  succes- 
sional modification  of  these  is  also  characteristic.  The  bones  of 
the  second  row  of  the  carpus  are  four  in  number,  but  as  the  toes 
are  reduced,  in  the  lines  of  the  hoofed  animals,  the  inner  (tra- 
pezium) is  soon  dropped,  and  the  second  (trapezoides)  becomes 
united  with  the  third  (magnum).  In  the  carnivorous  order,  the 
trapezoides  is  always  separate,  but  the  inner  pair  of  bones  of  the 
first  row  (scaphoid  and  the  lunar)  become  consolidated  into  a  single 
mass,  although  their  original  distinctness  is  easily  determined  by 
examination  of  the  foetus. 

The  two  bones  of  the  leg  which  articulate  with  the  foot  and 
hand,  exhibit  a  succession  of  changes  of  relation  in  progress  to- 
ward the  more  specialized  types.  In  the  Corypliodon  and  Umta- 
therium  of  the  Eocene,  each  of  these  bones  has  considerable  share 
in  the  articulation  ;  but  as  we  rise  in  the  series,  the  surface  of  at- 
tachment of  the  lesser  bones,  the  fibula  in  the  foot,  and  the  ulna 
in  the  hand,  becomes  successively  smaller,  until  in  the  ruminants 
the  fibula  is  almost  obliterated,  its  distal  end  remaining  as  a  small 
tuberosity  coossified  to  the  side  of  the  end  of  the  tibia.  In  the 
same  manner  the  articular  end  of  the  ulna  in  the  fore  leg  is  suc- 
cessively reduced,  until  this  bone  also  becomes  a  thin  strip  coossi- 
fied to  the  lower  side  of  the  radius,  with  no  distinct  termination. 


PLATE   VIL 


pec... 


Fia.  5. 


Fig.  7. 


acQ 


-ax 


Fig.  9. 


acc 


Fig.  2. 


Fig.  4. 


ktti' ai       pi 


pi    Pe       ji 

Fig.  6. 


ai    aV  P} 


Fig.  8. 


ae    y 


—-h 


ye 


Fig.  10. 


Fig.  1,  Mioclaenus  corrxigatus^  superior  molars.  Fisf.  2,  Pantolambda  hathmodon^ 
superior  true  molars.  Fig.  3,  Phenacodus  primcevus,  superior  molar.  Fig.  4,  do.  inferior 
molar.  Fig.  5,  Lambdotherium  popoagicum^  superior  molar.  Fig.  6,  do.  inferior  molar. 
Fig.  7,  AncMtherium  anrelianense,  superior  molar.  Fig.  8,  Hippotlieriu'm  gracile^  infe- 
rior molar.  Fig.  9,  superior  molar  young  crown  of  a  Hippotherium.  Fig.  10,  superior 
molar  of  Equus.  Figs.  1,  2,  5,  6,  from  Cope  ;  3, 4,  from  Wortman ;  the  others  from 
'"audry. 


G: 


276        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

in  both  the  horse  and  the  ox.  In  the  foetus  these  bones  are  well 
distinguished. 

The  dentition  tells  as  clearly  as  possible  the  same  story.  Here, 
again,  as  I  have  pointed  out  in  a  paper  on  the  **  Homologies  and 
Origin  of  the  Types  of  Dentition  of  the  Mammalia  Educahilia,^'' 
the  most  specialized  forms  of  dental  structure  are  presented  by  the 
horse,  the  ox,  and  the  tiger.  But  they  are  all  modifications  of  a 
single  type  of  tooth,  viz.,  an  oval  crown  supporting  four  tubercles 
on  the  summit,  in  the  lower  jaw,  and  three  or  four  in  the  upper 
jaw.  In  the  lower  cutting  molar  of  the  cat  but  one  of  these  tu- 
bercles remains,  forming  with  another  in  front  of  it  a  double  shear 
blade,  whose  development  may  be  traced  from  its  earliest  begin- 
nings in  the  genera  of  the  Eocene.  In  the  odd-toed  forms  (tapir, 
rhinoceros,  etc.)  the  tubercles  become  connected  transversely, 
forming  cross-crests,  and  the  outer  ones  are  generally  flattened  on 
the  outer  side.  In  the  horse  the  tubercles  have  a  very  complex 
form,  and  the  spaces  between  them  filled  by  a  peculiar  substance, 
the  cementum.  In  the  ruminants  the  tubercles  come  to  have  a 
crescent-shaped  section  and  are  drawn  out  to  an  enormous  length, 
forming  a  prismatic  tooth  :  here,  also,  the  intervening  deep  valleys 
are  filled  with  cementum.  .  In  the  third  series,  that  of  the  ele- 
phant, the  original  tubercles  (permanently  separate  in  the  masto- 
dons) are  connected  into  cross-crests,  which  are  drawn  out  to  a 
great  length,  and  as  in  the  other  series  are  supported  by  a  deposit 
of  hard  cementum  in  the  intervening  valleys.  The  transitions  be- 
tween these  and  the  primitive  four-tubercled  molar  are  numerous 
and  direct. 

There  is  not  now  opportunity  to  consider  the  question  of  tran- 
sition from  type  to  type  by  descent,  further  than  to  indicate  by  a 
few  examples  the  manner  in  which  it  has  evidently  occurred. 
This  has  been  by  unequal  growth  of  parts  during  foetal  life,  ac- 
cording to  the  laws  of  acceleration  and  retardation.  The  union 
of  the  two  basal  bones  of  toes  into  a  single  one  (the  "cannon- 
bone  ")  in  the  ruminants,  is  accomplished  by  the  more  and  more 
rapid  completion  of  the  process  of  ossification  in  the  growth  of 
those  bones  ;  the  confluence  of  the  various  carpal  and  tarsal  bones 
in  various  orders  has  the  same  history.  In  many  genera  it  has 
been  observed  that  the  milk  dentition  has  resemblances  to  other 
and  older  dentitions,  which  entirely  disappear  in  the  permanent 
teeth.  This  is  the  case  with  Coryphodon  and  Equus ;  while  it 
may  be  observed  in  the  kitten,  whose  sectorial  milk-tooth  has  the 


PLATE  VIII. 


278        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

heel  belonging  to  all  the  lower  and  primitive  Carnivora  which  is 
wanting  from  the  sectorial  of  the  adult  cat.  Moreover,  in  complex 
teeth,  the  different  stages  of  wear  represent  primitive  conditions 
of  the  same  animal,  elsewhere  preserved  to  us  in  extinct  adult 
genera  and  species. 

Forms  which  violate  the  definitions  of  the  orders  above  given 
are  also  well  known.  Thus  Mesonyx,  with  the  skull  and  denti- 
tion of  a  carnivore,  has  the  separate  scaphoid  and  lunar  bones  and 
flat  claws  or  hoofs  of  an  ungulate.  Calamodon  has  the  molars 
of  an  ungulate,  the  incisors  of  a  rodent,  and  claws  resembling 
somewhat  those  of  a  carnivore.  Uintatlierium  has  feet  partly  like 
an  elephant,  and  teeth  of  a  tapir. 

I  have  referred  the  Mammalia  with  five  and  four  toes,  the  full 
number  of  distinct  tarsal  and  carpal  bones,  which  form  interlock- 
ing series,  and  in  which  the  tread  is  plantigrade,  to  a  new  order 
called  the  AmUyjJoda.  These  represent  the  primitive  type  of  the 
higher  Mammalia  with  convoluted  brains,  etc.,  but  present  much 
variation  in  the  constitution  of  the  teeth.  From  the  latter  have 
come  off  not  only  the  three  hoofed-orders  represented  by  the  ele- 
phant, the  horse,  and  the  ox,  but  the  origin  of  the  Carnivora  and 
Quadrwnana  is  scarcely  distinguishable  from  it,  if  at  all ;  while 
there  is  little  doubt  that  the  natatory  Sireniaii  order  was  derived 
from  it  by  a  process  of  degradation,  chiefly  of  the  extremities,  in 
connection  with  the  assumption  of  an  aquatic  life.  The  mana- 
tee, of  which  a  fine  example  may  now  be  seen  in  our  zoological 
gardens,  represents  this  division. 

The  relation  of  man  to  this  history  is  highly  interesting.  Thus 
in  all  general  points  his  limbs  are  those  of  the  primitive  type  so 
common  in  the  Eocene.  He  is  plantigrade,  has  five  toes,  separate 
carpals  and  tarsals  ;  short  heel,  rather  flat  astragalus,  and  neither 
hoofs  nor  claws,  but  something  between  the  two.  The  bones  of 
the  forearm  and  leg  are  not  so  unequal  as  in  the  higher  types,  and 
remain  entirely  distinct  from  each  other,  and  the  ankle-joint  is 
not  so  perfect  as  in  many  of  them.  In  his  teeth  his  character  is 
thoroughly  primitive.  He  possesses,  in  fact,  the  original  quadri- 
tuberculate  molar  with  but  little  modification.  His  structural 
superiority  consists  solely  in  the  complexity  and  size  of  his  brain. 
The  forms  of  the  quadrumanous  order,  while  agreeing  with  each 
other  in  most  respects,  display  the  greatest  range  of  brain  struct- 
ure, and  show  that  while  they  have  made  but  little  progress  since 
the  Eocene  in  perfection  of  organization  of  the  skeleton,  they 


PLATE  IX. 


Fig.  7. 


Fig.  1. 


Fig.  4. 


C   V  ^ 


Fig.  5. 


Fig.  6. 


Fig.  8. 


COMPAEISOK   BETWEEN   THE   DENTITION   OF   THE   LEirtJE   AnAPTOMORPHUS   AND   MaN. 

Fig.  1,  skull  of  Anaptomovplixis  Tiormmctdus^  natural  size.  Fig.  2,  same,  oblique 
view,  displaying  the  large  cerebral  hemispheres  ;  compare  Plate  XIV  for  relatively  small 
size  in  a  contemporary  (Fig.  3)  or  a  successor  in  time  (Fig.  2).  Fig.  3,  superior  view  of 
skull,  natural  size.  Fig.  4,  inferior  view,  3/2  natural  size.  Figs.  5,  6,  and  7,  left  branch  of 
lower  jaw  of  Anaptomorphus  cemulus,  twice  natural  size;  5,  from  left  side;  6,  inner 
Bide ;  7,  from  above.  Fig.  8,  superior  dentition  of  Homo  sapiens  (from  Alien),  natural 
size. 


280        THE  STRUCTURAL  EVIDENCE  OF  EVOLUTION. 

accom23lished  a  mucli  greater  work,  the  eyolution  of  tlie  human 
brain  and  its  functions. 

A  very  important  lesson  is  derived  from  these  and  kindred  facts. 
The  monkeys  were  anticipated  in  the  greater  fields  of  the  world's 
activity  by  more  powerful  rivals ;  the  ancestors  of  the  ungulates 
held  the  fields  and  the  swamps,  and  the  Carnivora,  driven  by  hun- 
ger, learned  the  arts  and  cruelty  of  the  chase.  The  weaker  an- 
cestors of  the  Quadrumana  possessed  neither  speed  nor  weapons 
of  offense  and  defense,  and  nothing  but  an  arboreal  life  was  left 
them,  where  they  developed  the  prehensile  powers  of  the  feet. 
Their  digestive  system  unspecialized,  their  food  various,  their  life 
the  price  of  ceaseless  vigilance,  no  wonder  that  that  quality  of  in- 
quisitiveness  and  wakefulness  was  stimulated  and  developed  which 
is  the  condition  of  progressive  intelligence.  So  *'  the  race  has  not 
been  to  the  swift  nor  the  battle  to  the  strong" ;  the  *' survival  of 
the  fittest"  has  been  the  survival  of  the  most  intelligent,  and 
natural  selection  proves  to  be,  in  its  highest  animal  phase,  intel- 
ligent selection. 


IX. 

THE  DEVELOPMENTAL  SIGNIFICANCE   OF  HUMAN 

PHYSIOGNOMY.* 

The  ability  to  read  character  in  the  form  of  the  human  face 
and  figure  is  a  gift  possessed  by  comparatively  few  persons,  al- 
though most  people  interpret,  more  or  less  correctly,  the  salient 
points  of  human  expression.  The  transient  appearances  of  the 
face  reveal  temporary  phases  of  feeling  which  are  common  to  all 
men  ;  but  the  constant  qualities  of  the  mind  should  be  expressed, 
if  at  all,  in  the  permanent  forms  of  the  executive  instrument  of 
the  mind,  the  body.  To  detect  the  peculiarities  of  the  mind  by 
external  marks  has  been  the  aim  of  the  physiognomist  of  all 
times  ;  but  it  is  only  in  the  light  of  modern  evolutionary  science 
that  much  progress  in  this  direction  can  be  made.  The  mind,  as 
a  function  of  part  of  the  body,  partakes  of  its  perfections  and  its 
defects,  and  exhibits  parallel  types  of  development.  Every  pecu- 
liarity of  the  body  has  probably  some  corresponding  significance  in 
the  mind,  and  the  causes  of  the  former  are  the  remoter  causes  of 
the  latter.  Hence,  before  a  true  physiognomy  can  be  attempted, 
the  origin  of  the  features  of  the  face  and  general  form  must  be 
known.  Not  that  a  perfect  physiognomy  will  ever  be  possible.  A 
mental  constitution  so  complex  as  that  of  man  can  not  be  expected 
to  exhibit  more  than  its  leading  features  in  the  body ;  but  these 
include,  after  all,  most  of  what  it  is  important  for  us  to  be  able  to 
read  from  a  practical  point  of  view. 

The  present  essay  will  consider  the  probable  origin  of  the 
structural  points  which  constitute  the  permanent  expression. 
These  may  be  divided  into  three  heads,  viz.  :  (1)  Those  of  the 
general  form  or  figure  ;  (2)  those  of  the  surface  or  integument  of 
the  body  with  its  appendages  ;  and  (3)  those  of  the  forms  of  the 

*  Abstract  of  a  lecture  delivered  before  the  Franklin  Institute  of  Philadelphia, 
January  20,  1881,  in  exposition  of  principles  laid  down  in  "The  Hypothesis  of  Evo- 
lution," New  Haven,  1870,  p.  31. 


282        THE   STRUCTURAL  EVIDEN^OE   OF  EVOLUTION". 

head  and  face.     The  principal  points  to  be  considered  under  each 
of  these  heads  are  the  following  : 

7.   The  General  Form. 

1.  The  size  of  the  head. 

2.  The  squareness  or  slope  of  the  shoulders. 

3.  The  length  of  the  arms. 

4.  The  constriction  of  the  waist. 

5.  The  width  of  the  hips. 

6.  The  length  of  the  leg,  principally  of  the  thigh. 

7.  The  sizes  of  the  hands  and  feet. 

8.  The  relatiye  sizes  of  the  muscles. 

//.   The  Surfaces. 

9.  The  structure  of  the  hair  (whether  curled  or  not). 

10.  The  length  and  position  of  the  hair. 

11.  The  size  and  shape  of  the  nails. 

12.  The  smoothness  of  the  skin. 

13.  The  color  of  the  skin,  hair,  and  irides. 

III.   The  Head  and  Face. 

14.  The  relative  size  of  the  cerebral  to  the  facial  regions. 

15.  The  prominence  of  the  forehead. 

16.  The  prominence  of  the  superciliary  (eyebrow)  ridges. 

17.  The  prominence  of  the  alveolar  borders  (jaws). 

18.  The  prominence  and  width  of  the  chin. 

19.  The  relation  of  length  to  width  of  skull. 

20.  The  prominence  of  the  malar  (cheek)  bones. 

21.  The  form  of  the  nose. 

22.  The  relative  size  of  the  orbits  and  eyes. 

23.  The  size  of  the  mouth  and  lips. 

The  significance  of  these,  as  of  the  more  important  structural 
characters  of  man  and  the  lower  animals,  must  be  considered  from 
two  standpoints,  the  paleontological  and  the  embryological.  The 
immediate  paleontological  history  of  man  is  unknown,  but  may 
be  easily  inferred  from  the  characteristics  displayed  by  his  nearest 
relatives  of  the  order  Quadrumana.  If  we  compare  these  animals 
with  man,  we  find  the  following  general  differences.  The  num- 
bers correspond  to  those  of  the  list  above  given. 


HUMAN   PHYSIOGNOMY. 


283 


/.  As  to  General  Form, — (3)  In  the  apes  the  arms  are  longer  ; 
(8)  the  extensor  muscles  of  the  leg  are  smaller. 

//.  As  to  Surface, — (9)  The  body  is  covered  with  hair  which 
is  not  crisp  or  woolly  ;  (10)  the  hair  of  the  head  is  short ;  (13)  the 
color  of  the  skin,  etc.,  is  dark, 

///.  As  to  Head  and  Face. — (14)  The  facial  region  of  the 
skull  is  large  as  compared  with  the  cerebral ;  (15)  the  forehead  is 


Fig.  52. — Section  of  skull  of  adult  orang-outang  {Simla  safyrus).  «,  section  of 
skull  of  young  orang,  showing;  relatively  shorter  jaws  and  more  prominent  cerebral 
region. 

not  prominent,  and  is  generally  retreating ;  (16)  the  superciliary 
ridges  are  more  prominent ;  (17)  the  edges  of  the  jaws  are  more 
prominent ;  (18)  the  chin  is  less  prominent ;  (20)  the  clieek-bones 
are  more  prominent ;  (21)  the  nose  is  without  bridge,  and  with 
short  and  flat  cartilages  ;  (22)  the  orbits  and  eyes  are  smaller 
(except  in  Nyctipithecus)  ;  (24)  the  mouth  is  small  and  the  lips 
are  thin. 

It  is  evident  that  the  possession  of  any  one  of  the  above  char- 
acteristics by  a  man  approximates  him  more  to  the  monkeys,  so 


284:        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 


far  as  it  goes.     He  retains  features  wliicli  have  been  obliterated  in 
other  persons  in  the  process  of  evolution. 

In  considering  the  ph3'siognomy  of  man  from  an  embryological 
standpoint,  we  must  consider  the  peculiarities  of  the  infant  at 
birth.  The  numbers  of  the  following  list  correspond  with  those 
already  used  (Fig.  53). 

/.  As  to  the  General  Form. — (1)  The  head  of  the  infant  is  rel- 
atively much  larger  than  in  the  adult ;  (3)  the  arms  are  relatively 

longer;  (4)  there  is  no  waist; 
(6)  the  legs,  and  especially 
the  thighs,  are  much  shorter, 
//.  As  to  the  Surfaces. — 
(10)  The  body  is  covered  with 
fine  hair,  and  that  of  the 
head  is  short. 

///.  The  Head  and  Face. 
— (14)  The  cerebral  part  of 
the  skull  greatly  j^redomi- 
nates  over  the  facial ;  (16) 
the  superciliary  ridges  are 
not  developed ;  (17)  the  al- 
veolar borders  are  not  prom- 
inent ;  (20)  the  malar  bones 
are  not  prominent ;  (21)  the 
nose  is  without  bridge  and 
the  cartilages  are  flat  and 
generally  short ;  (22)  the 
eyes  are  larger. 

It  is  evident  that  per- 
sons who  present  any  of  the 
characters  cited  in  the  above 
list  are  more  infantile  or  em- 
bryonic in  those  respects  than 
are  others  ;  and  that  those  who  lack  them  have  left  them  behind 
in  reaching  maturity. 

We  have  now  two  sets  of  characters  in  which  men  may  differ 
from  each  other.  In  the  one  set  the  characters  are  those  of  monk- 
eys, in  the  other  they  are  those  of  infants.  Let  us  see  whether 
there  be  any  identities  in  the  two  lists,  i.  e.,  whether  there  be  any 
of  the  monkey-like  characters  which  are  also  infantile.  We  find 
the  following  to  be  such  : 


Fig.  53. — ^Figure  of  infant  at  birth;  a,  front 
of  face. 


huma:n'  physiognomy. 


285 


L  As  to  General  Form. — (3)  The  arms  are  longer. 

//.  Surface. —  (10)  The  hair  of  the  head  is  short,  and  the  hair 
on  the  body  is  more  distributed. 

///.  As  to  Head  and  Face. — (21)  The  nose  is  without  bridge, 
and  the  cartilages  are  short  and  flat. 

Three  characters  only  out  of  twenty- three.  On  the  other  hand, 
the  following  characters  of  monkey-like  significance  are  the  oppo- 
sites  of  those  included  in  the  embryonic  list  :  (14)  The  facial  re- 
gion of  the  skull  is  large  as  compared  with  the  cerebral ;  (15)  the 
forehead  is  not  prominent ;  (16)  the  superciliary  ridges  are  more 


¥iQ.  54. 


i'lG.  55. 


Fig.  54. — Portrait  of  a  girl  at  five  years  of  age.  Fig.  55. — Portrait  of  the  same  at 
seventeen  years,  showing  the  elongation  of  the  facial  region,  and  less  protuberance  of 
the  cerebral. 


prominent  ;  (17)  the  edges  of  the  jaws  are  more  prominent.  Four 
characters,  all  of  the  face  and  head.  It  is  thus  evident  that  in  at- 
taining maturity  man  resembles  more  and  more  the  apes  in  some 
important  parts  of  his  facial  expression. 

It  must  be  noted  here  that  the  difference  between  the  young 
and  embryonic  monkeys  and  the  adults  is  quite  the  same  as  those 
just  mentioned  as  distinguishing  the  young  from  the  adult  of  man 
(Figs.  1-2).  The  change,  however,  in  the  case  of  the  monkeys  is 
greater  than  in  the  case  of  man.  That  is,  in  the  monkeys  the 
jaws  and  superciliary  ridges  become  still  more  prominent  than  in 


PLATE  X. 


Esequibo  Indian  women,  showing  the  following  peculiarities  :  deficient  bridge  of 
nose,  prognathism,  no  waist,  and  deficiency  of  statm-e  through  short  femur.  From 
photographs  by  Endlich. 


HUMAN  PHYSIOGNOMY. 


287 


man.  As  these  characters  result  from  a  fuller  course  of  growth, 
from  the  infant,  it  is  evident  that  in  these  respects  the  apes  are 
more  fully  developed  than  man.  Man  stops  short  in  the  develop- 
ment of  the  face,  and  is  in  so  far  more  embryonic*  The  promi- 
nent forehead  and  reduced  jaws  of  man  are  characters  of  "  retar- 
dation." The  characters  of  the  prominent  nose,  with  its  elevated 
bridge,  is  a  result  of  ^*  acceleration,"  since  it  is  a  superaddition  to 
the  quadrumanous  type  from  both  the  standpoints  of  paleontology 
and  embryology. f  The  development  of  the  bridge  of  the  nose  is 
no  doubt  directly  connected  with  the  development  of  the  front  of 
the  cerebral  j)art  of  the  skull  and  ethmoid  bone,  which  sooner  or 
later  carries  the  nasal  bones  with  it. 

If  we  now  examine  the  leading  characters  of  the  physiognomy 
of  three  of  the  principal  human  sub-sj)ecies,  the  Negro,  the  Mon- 


FiG.  56. 


Fig.  57. 


Fig.  56, — Profile  of  a  Lucliatze  negro  woman,  sbowin;?  deficient  bridge  of  nose  and 
chin,  and  elongate  facial  region  and  prognathism.  Fig.  57. — Face  of  another  Luchatze, 
showing  flat  nose,  less  prognathism  and  larger  cerebral  region.     From  Serpa  Pinto. 

golian,  and  the  Indo-European,  we  can  readily  observe  that  it  is 
in  the  two  first  named  that  there  is  a  predominance  of  the  quad- 
rumanous features  which  are  retarded  in  man  ;  and  that  the  em- 
bryonic characters  which  predominate,  are  those  in  which  man  is 


*  Thi3  fact  has  been  well  stated  by  C.  S.  Minot,  in  the  "Naturalist "  for  1882, 
p.  511. 

f  See  Cope,  "  The  Hypothesis  of  Evolution,"  New  Haven,  1870,  p.  31. 


288 


THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION 


accelerated.     In  race  description  the  prominence  of  the  edges  of 

the  jaws  is  called  prognathism,  and  its  absence  orthognathism. 

The  significance  of  the  two  lower  race  characters,  as  compared 

with  those  of  the  Indo-European,  is  as  follows  : 

Negro. — Hair  crisp  (a  special  character),  short  (quadrnm.  ac- 

cel.)  ;  prognathous  (quadrum.  accel.) ;  nose  flat,  without  bridge 

(quadrum.  retard.)  ;*  malar  bones  prominent  (quadrum.  accel.) ; 

beard  short  (quadrum.  retard.) ;  arms  longer  (quadrum.  accel.) ; 

extensor  muscles  of  legs  small  (quadrum.  retard.). 

Mongolian. — Hair  straight,  long  (accel.)  ;  jaws  prognathous 

(quadrum.  accel.) ;  nose  flat  or  prominent,  with  or  without  bridge  ; 

malar  bones  prominent 
(quadrum.  accel.) ;  beard 
none  (embryonic)  ;  arms 
shorter  (retard.) ;  extensor 
muscles  of  leg  (''calf") 
smaller  (quad,  retard.). 

Indo-European.  — Hair 
long  (accel.) ;  jaws  orthog- 
nathous  (embryonic  re- 
tard.) ;  nose  (generally) 
prominent  with  bridge 
(accel.) ;  malar  bones  re- 
duced (retard.) ;  beard 
long  (accel.);  arms  shorter 
(retard.) ;  extensor  mus- 
cles of  the  leg  large  (accel.). 
The  Indo  -  European 
race  is  then  the  highest  by 
virtue  of  the  acceleration 
of  growth  in  the  develop- 
ment of  the  muscles  by 
which  tiie  body  is  main- 
tained in  the  erect  position 

Fig.  58.— Portrait  of  Satauta,  a  late  chief  of  the  (extensorS  of  the  leg),  and 

Kiowas  (from  the  Ked  Eiver  of  Texas),  from  a  j^    those     important     elc- 
pfiotoarraph.     The  predominance  of  the  facial  re-  +        -p    v.        i 

gion,  and  especially  of  the  malar  bones,  and  the  ^^nts    01    beauty,   a    WCll- 

absence  of  beard,  are  noteworthy.  developed  nose  and  beard. 


*  In  the  Bochimans,  the  flat  nasal  bones  are  coossified  with  the  adjacent  ele- 
ments as  in  the  apes  (Thulie). 


PLATE  XL 


'■'V;;:;:Vi;:V;::;/;r'!'-. 


^'S^\ii\^■'l■■r,l,,;■\^.v.i\\\t,</,:■■■,■,'.l;i■ri■  ,■:••-.•. 


j^- -'--,.A','f»J^i^r^v?,.V,y.V^»>';I'.'->a 


The  Wrestler ;  original  in  the  Vatican.     This  figure  displays  the  characters  of  the 
male  Indo-European,  except  the  beard. 
19 


290        THE   STRUCTURAL  EVIDENCE  OF  EYOLUTION. 

It  is  also  superior  in  those  points  in  which  it  is  more  embryonic 
than  the  other  races,  viz.,  the  want  of  prominence  of  the  jaws 
and  cheek-bones,  since  these  are  associated  with  a  greater  predom- 
inance of  the  cerebral  part  of  the  skull,  increased  size  of  cerebral 
hemispheres,  and  greater  intellectual  power. 

A  comparison  between  the  two  sexes  of  the  Indo-Europeans 
expresses  their  physical  and  mental  relations  in  a  definite  way.  I 
select  the  sexes  of  the  most  civilized  races,  since  it  is  in  these,  ac- 
cording to  Broca  and  Topinard,  that  the  sex  characters  are  most 
pronounced.  They  may  be  contrasted  as  follows.  The  numbers 
are  those  of  the  list  on  page  282,  already  used.  I  first  consider 
those  which  are  used  in  the  tables  of  embryonic,  quadrumanous, 
and  race  characters  : 

MALE.  FEMALE. 

/.   The  General  Form. 

2.  Shoulders  square.  Shoulders  sloped. 

4.  Waist  less  constricted.  Waist  more  constricted. 

5.  Hips  narrower.  Ilips  wider. 

6.  Legs  longer.  Legs  shorter  (very  frequently). 
8.  Muscles  larger.  Muscles  smaller. 

II.  The  Integuments^  etc. 

10.  More  hair  on  body,  that   of   head       Less  hair  on  body,  that  of  head  longer ; 

shorter ;  beard.  no  beard. 

12.  Skin  rougher  (generally).  Skin  smoother. 

III.  TJie  Head  and  Face. 

16.  Superciliary  ridges  more  prominent.       Superciliary  ridges  low, 
22.  Eyes  often  smaller.  Eyes  often  larger. 

The  characters  in  which  the  male  is  the  most  like  the  infant 
are  two,  viz.,  the  narrow  hips  and  short  hair.  Those  in  which  the 
female  is  most  embryonic  are  five,  viz.,  the  shorter  legs,  smaller 
muscles,  absence  of  beard,  low  superciliary  ridges,  and  frequently 
larger  eyes.  To  these  may  be  added  two  others  not  mentioned  in 
the  above  lists  ;  these  are  (1)  the  high-pitched  voice,  which  never 
falls  an  octave  as  does  that  of  the  male  ;  and  (2)  the  structure  of 
the  generative  organs,  which  in  all  Mammalia  more  nearly  resem- 
ble the  embryo  and  the  lower  Vertebrata,  in  the  female  than  in  the 
male.  Nevertheless,  as  Bischoff  has  pointed  out,  one  of  the  most 
important  distinctions  between  man  and  the  apes  is  to  be  found 
in  the  external  reproductive  organs  of  the  female. 

From  the  preceding  summary  sketch  the  reader  will  be  able  to 
explain  the  meaning  of  most  of  the  peculiarities  of  face  and  form 


HUMAIT  PHYSIOGNOMY. 


291 


which  he  will  meet  with.  Many  persons  possess  at  least  one  quad- 
rumanous  or  embryonic  character.  The  strongly  convex  upper  lip 
frequently  seen  among  the  lower  classes  of  the  Irish  is  a  modified 
quadrumanous  character.  Many  people,  especially  those  of  the 
Sclavic  races,  have  more  or  less  embryonic  noses.  A  retreating 
chin  is  a  marked  monkey  character.    Shortness  of  stature  is  mostly 


Fig.  59, — Australian  native  (from  Brough  Smyth),  showing  small  development  oi 
muscles  of  legs,  and  prognathism. 

due  to  shortness  of  the  femur,  or  thigh  ;  the  inequalities  of  people 
sitting  are  much  less  than  those  of  people  standing.  A  short  femur 
is  embryonic  ;  so  is  a  very  large  head.  The  faces  of  some  people 
are  partially  embryonic,  in  having  a  short  face  and  light  lower 
jaw.  Such  faces  are  still  more  embryonic  when  the  forehead  and 
eyes  are  protuberant.     Retardation  of  this  kind  is  most  frequently 


PLATE    XIL 


The  Venus  of  the  Capitol  (Rome).     The  form  and  face  present  the  characteristic 
paculiarities  of  the  female  of  the  Indo-European  race. 


HUMAN  PHYSIOGNOMY.  293 

seen  in  children,  and  more  frequently  in  women  than  in  men.  The 
length  of  the  arms  would  appear  to  have  grown  less  in  compar- 
atively recent  times.  Thus  the  humerus  in  most  of  the  Greek 
statues,  including  the  Apollo  Belvidere,  is  longer  than  those  of 
modern  Europeans,  according  to  a  writer  in  the  '^Bulletin  de  la 
Societe  d' Anthropologic  "  of  Paris,  and  resembles  more  nearly  that 
of  the  modern  Nubians  than  any  other  people.  This  is  a  quad- 
rumanous  approximation.  The  miserably  developed  calves  of 
many  of  the  savages  of  Australia,  Africa,  and  America,  are  well 
known.  The  fine  swelling  gastrocnemius  and  soleus  muscles  char- 
acterize the  highest  races,  and  are  most  remote  from  the  slender 
shanks  of  the  monkeys.  The  gluteus  muscles  developed  in  the 
lower  races  as  well  as  in  the  higher,  distinguish  them  well  from 
the  monkeys  with  their  flat  posterior  outline. 

It  must  be  borne  in  mind  that  the  quadrumanous  indications 
are  found  in  the  lower  classes  of  the  most  developed  races.  The 
status  of  a  race  or  family  is  determined  by  the  percentage  of  its 
individuals  who  do  and  do  not  present  the  features  in  question. 
Some  embryonic  characters  may  also  appear  in  individuals  of  any 
race,  as  a  consequence  of  special  circumstances.  Such  are,  how- 
ever, as  important  to  the  physiognomist  as  the  more  normal  vari- 
ations. 

Some  of  these  features  have  a  purely  physical  significance,  but 
the  majority  of  them  are,  as  already  remarked,  intimately  con- 
nected with  the  development  of  the  mind,  as  an  effect  or  necessary 
coincidence.     I  will  examine  these  relations  in  a  future  article. 


X. 

THE  EVIDENCE  FOR  EVOLUTION  IN    THE   HIS- 
TORY  OF  THE  EXTINCT  MAMMALIA.* 

The  subject  to  which  I  wish  to  call  your  attention  this  morn- 
ing requires  neither  preface  nor  apology,  as  it  is  one  with  the  dis- 
cussion of  which  you  are  perfectly  familiar.  I  bring  it  before  the 
general  session  of  the  Association  in  view  of  the  fact  that  you 
are  all  familiar  with  it  in  a  general  way,  and  that  it  probably  in- 
terests the  members  of  sections  who  do  not  pursue  the  sjoecial 
branch  to  which  it  refers,  as  well  as  those  who  do  :  also,  since  it 
has  been  brought  before  us  in  various  public  addresses  for  many 
years,  during  the  meetings  of  this  Association,  I  thought  it  might 
be  well  to  introduce  it  at  this  meeting,  in  order  that  we  might 
not  omit  to  have  all  the  sides  of  it  presented. 

The  interests  which  are  involved  in  it  are  large  :  they  are 
chiefly,  however,  of  a  mental  and  metaphysical  character ;  they 
do  not  refer  so  much  to  industrial  and  practical  interests,  nor  do 
they  inyolve  questions  of  applied  science.  They  involve,  however, 
questions  of  opinion,  questions  of  belief,  questions  which  affect 
human  happiness,  I  venture  to  say,  even  more  than  questions  of 
applied  science  ;  certainly,  which  affect  the  happiness  of  the 
higher  grades  of  men  and  women  more  than  food  or  clothing,  be- 
cause they  relate  to  the  states  of  our  mind,  explaining  as  they  do 
the  reasons  of  our  relations  to  our  fellow  beings,  and  to  all  other 
things  by  which  we  are  surrounded,  and  the  general  system  of  the 
forces  by  which  we  are  controlled.  So  it  has  always  appeared  to 
me  :  hence  I  have  selected  the  department  of  biology  for  study, 
and  have  taken  a  great  interest  in  this  aspect  of  it. 

The  doctrine  of  evolution,  as  taught  by  the  biologists  of  to- 
day, has  several  stages  or  parts  of  its  presentation.  First,  the 
foundation  principle  is  this  :  that  the  species  of  animals  and  of 


*  An  address  delivered  before  the  American  Association  for  the  Advancement  of 
Science,  1883. 


THE  EXTINCT  MAMMALIA.  295 

plants,  the  species  of  organic  beings,  as  well  as  the  yarious  natu- 
ral divisions  into  which  these  organic  beings  fall,  have  not  always 
been  as  we  see  them  to-day,  but  they  have  been  produced  by  a 
process  of  change  which  has  progressed  from  age  to  age  through 
the  influence  of  natural  laws  ;  that,  therefore,  the  species  which 
now  exist  are  the  descendants  of  other  species  which  have  existed 
heretofore,  by  the  ordinary  processes  of  reproduction  ;  and  that 
all  the  various  structures  of  organic  beings,  which  make  them 
what  they  are,  and  which  compel  them  to  act  as  they  now  act, 
are  the  result  of  gradual  or  sudden  modifications  and  changes 
during  the  periods  of  geologic  time.  That  is  the  first  phase  or 
aspect  which  meets  the  naturalist  or  biologist. 

Another  phase  of  the  question  relates  to  the  origin  of  that  life 
itself  which  is  supposed  to  inhabit  or  possess  organic  beings. 
There  is  an  hypothesis  of  evolution  which  derives  this  life  from 
no-life,  which  derives  vitality  from  non-vitality.  This  is  another 
branch  of  the  subject,  to  which  I  can  not  devote  much  attention 
to-day. 

There  is  still  another  department  of  the  subject,  which  relates 
to  the  origin  of  mind,  and  which  derives  the  mental  organization 
of  the  higher  animals,  especially  of  man,  from  pre-existent  types 
of  mental  organization.  This  gives  us  a  genealogy  of  mind,  a  his- 
tory of  the  production  or  creation  of  mind,  as  it  is  now  j^resented 
in  its  more  complex  aspects  as  a  function  of  the  human  brain. 
This  aspect  of  the  subject  is,  of  course,  interesting  ;  and  upon 
it  I  can  touch  with  more  confidence  than  upon  the  question  of 
the  origin  of  life. 

Coming  now  to  the  question  of  the  origin  of  structures,  we 
have  by  this  time  accumulated  a  vast  number  of  facts  which  have 
been  collated  by  laborious  and  faithful  workers,  in  many  countries 
and  during  many  years  ;  so  that  we  can  speak  with  a  good  deal  of 
confidence  on  this  subject  also.  As  to  the  phenomena  which 
meet  the  student  of  zoology  and  botany  at  every  turn,  I  would 
merely  repeat  what  every  one  knows — and  I  beg  pardon  of  my  bio- 
logical friends  for  telling  them  a  few  well-known  truths,  for  there 
may  be  those  present  who  are  not  in  the  biological  section — the 
phenomena  which  meet  the  student  of  biology  come  under  two 
leading  classes.  The  first  is  the  remarkable  fidelity  of  species  in 
reproducing  their  like.  *^  Like  produces  like,"  is  the  old  theo- 
rem, and  is  true  in  a  greiat  many  cases  ;  just  as  coins  are  struck 
from  the  die,  just  as  castings  are  turned  out  from  a  common 


296        THE   STRUCTURAL  EVIDEXCK   OF  EYOLUTIOi^. 

mold.  It  is  one  of  the  most  wonderful  phenomena  of  nature, 
that  such  complex  organisms,  consisting  of  so  many  parts,  should 
be  repeated  from  age  to  age,  and  from  generation  to  generation, 
with  such  surprising  fidelity  and  precision.  This  fact  is  the  first 
that  strikes  the  student  of  these  sciences.  The  first  impression 
of  the  ordinary  person  would  be,  that  these  things  must  continue 
unchanged.  When  I  began  to  study  zoology  and  botany,  I  was 
surprised  to  find  there  was  a  science  of  which  I  had  no  concep- 
tion, and  that  was  this  remarkable  reproduction  of  types  one 
after  another  in  continued  succession.  After  a  man  has  had 
this  idea  thoroughly  assimilated  by  his  honest  and  conscien- 
tious studies,  he  will  be  again  struck  with  another  class  of 
facts.  He  will  find,  not  unfrequently,  that  this  doctrine  does 
not  apply.  He  will  find  a  series  of  facts  which  show  that  many 
individuals  fail  to  coincide  with  their  fellows  precisely,  the  most 
remarkable  variations  and  the  most  remarkable  half-way  atti- 
tudes and  double-sided  aspects  occurring ;  and  he  will  come  to 
the  conclusion,  sooner  or  later,  that  like  does  not  produce  like  in 
some  animals  with  the  same  precision  and  fidelity  with  which  it 
is  accomplished  in  other  animals.  So  that  we  have  these  two 
classes  of  facts — the  one  relating  to,  and  expressing,  the  law  of 
heredity  ;  the  other  which  expresses  the  law  of  variation.  I 
should  not  like  to  say  which  class  of  facts  is  the  most  numerously 
presented  to  the  student.  In  the  present  fauna  we  find  many 
groups  of  species  and  varieties  ;  but  exactly  how  many  species  we 
have,  how  many  genera  and  families  we  have,  we  can  not  defi- 
nitely state.  The  more  precise  and  exact  a  person  is  in  his  defini- 
tion and  in  his  analysis,  the  more  definite  his  science  becomes, 
and  the  more  precise  and  scientific  his  work.  Biology  is  a  science 
of  analvsis  of  forms.  What  the  scales  are  to  the  chemist  and  the 
physicist,  the  rule  and  measure  are  to  the  biologist.  It  is  a  ques- 
tion of  dimension,  a  question  of  length  and  breath  and  thickness, 
a  question  of  curves,  a  question  of  crooked  shapes  or  simple 
shapes — rarely  simple  shapes,  mostly  crooked,  generally  bilateral. 
It  requires  that  one  should  have  a  mechanical  eye,  and  should 
have  also  something  of  an  artistic  eye,  to  appreciate  these  forms, 
to  measure  them,  and  to  be  able  to  compare  and  weigh  them. 

Now,  when  we  come  to  arrange  our  shapes  and  our  measure- 
ments, we  find,  as  I  said  before,  a  certain  number  of  identities, 
and  a  certain  number  of  variations.  This  question  of  variation 
is  so  common  and  so  remarkable,  that  it  becomes  perfectly  evi- 


THE  EXTINCT  MAMMALIA.  297 

dent  to  the  specialist  in  each  department,  that  like  does  not  at 
all  times  produce  like.  It  is  perfectly  clear,  and  I  will  venture 
the  assertion  that  nearly  all  the  biologists  in  this  room  will  bear 
me  witness,  that  variability  is  practically  unlimited  in  its  range, 
and  multiplied  in  the  number  of  its  examples.  That  is  to  say  : 
species  vary  by  adding  or  by  failing  to  retain  certain  characteris- 
tics ;  and  generic  and  other  characters  are  found  to  appear  or 
disappear  in  accordance  with  some  law  to  be  discussed  farther  on. 

I  believe  that  this  is  the  simplest  mode  of  stating  and  explain- 
ing the  law  of  variation :  that  some  forms  acquire  something 
which  their  parents  did  not  possess ;  and  that  those  which  ac- 
quire something  additional  have  to  pass  through  more  numerous 
stages  than  their  ancestors  ;  and  those  which  lose  something  pass 
through  fewer  stages  than  their  ancestors  ;  and  these  processes  are 
expressed  by  the  terms  *' acceleration  "  and  *^  retardation." 

Of  course  we  are  met  with  the  opposite  side  of  the  case — the 
law  of  heredity.  We  are  told  that  the  facts  there  are  not  ac- 
counted for  by  any  law  of  evolution  ;  that  we  can  not  pass  from 
one  class  of  facts  to  the  other  class  of  facts  ;  that  the  law  of  the 
one  class  is  not  that  of  the  other.  Here  is  a  question  of  rational 
processes,  of  ordinary  reason.  If  the  rules  of  chemistry  are  true 
in  America,  I  imagine  they  are  true  in  Australia  and  Africa,  al- 
though I  have  not  been  there  to  see.  If  the  law  of  gravitation  is 
effective  here,  I  do  not  need  to  go  to  Australia  or  New  Zealand 
to  ascertain  whether  it  be  true  there.  So,  if  we  find  in  a  group 
of  animals  a  law  sufficient  to  account  for  their  creation,  it  is  not 
necessary  to  know  that  others  of  their  relatives  have  gone  through 
a  similar  process.  I  am  willing  to  allow  the  ordinary  practical 
law  of  induction,  the  practical  law  of  inference,  to  carry  me  over 
these  gaps,  over  these  interruptions.  And  I  state  the  case  in  this 
way,  because  it  is  Just  here  that  some  people  differ  from  me,  and 
it  is  Just  here  that  I  say  the  simple  question  of  rationality  comes 
in.  I  can  not  believe  that  Nature's  laws  are  so  dissimilar,  so 
irregular,  so  inexact,  that  those  which  we  can  see  and  understand 
in  one  place  are  not  true  in  another  ;  I  also  believe  that  the  ques- 
tion of  geological  likelihood  is  similar  to  the  question  of  geo- 
graphical likelihood.  If  a  given  process  be  true  in  one  of  the 
geological  periods,  it  is  true  in  another  ;  if  it  be  true  in  one  part 
of  the  world,  it  is  true  in  another  ;  because  I  find  interruptions 
in  the  series  here,  it  does  not  follow  that  there  need  be  interrup- 
tions clear  through  from  age  to  age.     The  assumption  is  on  the 


298        THE   STRUCTUPwAL   EVIDENCE   OF   EVOLUTION. 

side  of  tlie  man  who  asserts  that  transitions  have  not  taken  place 
between  forms  which  are  now  distinct. 

We  are  told  that  we  find  no  sort  of  evidence  of  that  transition 
in  past  geological  periods  ;  we  are  assured  that  such  changes  have 
not  taken  place  ;  we  are  even  assured  that  no  such  sign  of  such 
transition  from  one  species  to  another  has  ever  been  observed — a 
most  astonishing  assertion  to  make  to  a  biologist,  or  hy  a  biolo- 
gist ;  and  such  persons  have  even  the  temerity  to  cite  such  a 
special  case  as  that  between  the  wolf  and  the  dog.  Many  of  our 
domestic  dogs  are  nothing  but  wolves,  which  have  been  modified 
by  the  hand  of  man  to  a  very  slight  extent  indeed.  Many  dogs, 
in  fact  nearly  all  dogs,  are  descendants  of  wild  species  of  various 
countries,  and  are  variously  modified. 

To  take  the  question  of  the  definition  of  species.  Supposing 
we  have  several  species  well  defined,  say  four  or  five.  In  the 
process  of  investigation  we  obtain  a  larger  number  of  individuals, 
many  of  which  betray  characters  which  invalidate  the  definitions. 
It  becomes  necessary  to  unite  the  four  or  five  species  into  one. 
And  so,  then,  because  our  system  requires  that  we  shall  have  ac- 
curate definitions  (the  whole  basis  of  the  system  is  definitions ; 
you  know  the  very  comprehension  of  the  subject  requires  defini- 
tions), we  throw  them  all  together,  because  we  can  not  define  all 
the  various  special  forms  as  we  did  before,  until  we  have  but  one 
species.  And  the  critic  of  the  view  of  evolution  tells  us,  ^^I  told 
you  so  !  There  is  but  one  species,  after  all.  There  is  no  such 
thing  as  a  connection  between  species  :  you  never  will  find  it." 
Now,  how  many  discoveries  of  this  kind  will  be  necessary  to  con- 
vince the  world  that  there  are  connections  between  species  ?  How 
long  are  we  to  go  on  finding  connecting  links,  and  putting  them 
together,  as  we  have  to  do  for  the  sake  of  the  definition,  and  then 
be  told  that  we  have,  nevertheless,  no  intermediate  forms  between 
species  ?  The  matter  is  too  plain  for  further  comment.  We 
throw  them  together,  simply  because  our  definitions  require  it. 
If  we  knew  all  the  known  individuals  which  have  lived,  we  should 
have  no  species,  we  should  have  no  genera.  That  is  all  there  is 
of  it.  It  is  simply  a  question  of  a  universal  accretion  of  material, 
and  the  collection  of  information.  I  do  not  believe  that  the  well- 
defined  groups  will  be  found  to  run  together,  as  we  call  it,  in  any 
one  geological  period,  certainly  in  no  one  recent  period.  We 
recognize,  however,  in  looking  backward,  tliat  they  converge  to 
a  wonderful  extent  :  one  group  has  diverged  at  one  period,  and 


THE   EXTINCT  MAMMALIA.  299 

another  one  has  become  diversified  in  a  different  period ;  and  so 
each  one  has  its  history,  some  beginning  farther  back  than  others, 
some  reaching  far  back  beyond  the  very  beginning  of  the  time 
when  fossils  could  be  preserved.  I  call  attention  to  this  view  be- 
cause it  is  a  very  easy  matter  for  us  to  use  words  for  the  purpose 
of  confusing  the  mind ;  for,  next  to  the  power  of  language  to  ex- 
press clear  ideas,  is  its  power  of  expressing  no  ideas  at  all.  As  we 
all  know,  we  can  say  many  things  which  we  can  not  tliink.  It  is 
a  very  easy  thing  to  say  twice  two  are  equal  to  six,  but  it  is  im- 
possible to  think  it. 

I  would  cite  what  I  mean  by  variations  of  species  in  one  of  its 
phases  :  I  mention  a  genus  of  snakes,  Ophibolus,  which  is  found 
in  the  United  States.  If  we  take  the  species  of  this  snake-genus 
as  found  in  the  Northern  States,  we  have  a  good  many  species  well 
defined.  If  we  go  to  the  Gulf  States,  and  examine  our  material, 
we  see  we  have  certain  other  species  well  defined,  and  they  are 
very  nicely  distinguished.  If,  now,  we  go  to  the  Pacific  coast,  to 
Arizona  and  New  Mexico,  we  shall  find  another  set  of  species 
well  defined  indeed.  If  we  take  all  these  different  types  of  our 
specimens  of  different  localities  together,  our  species,  as  the  Ger- 
mans say,  all  tumble  together  :  definitions  disappear,  and  we  have 
to  recognize,  out  of  the  preliminary  list  of  thirteen  or  fourteen, 
only  four  or  five.  That  is  simply  a  case  of  the  kind  of  fact  with 
which  every  biologist  is  perfectly  familiar. 

When  we  come  to  the  history  of  the  extinct  forms  of  life,  it  is 
perfectly  true  that  we  can  not  observe  the  process  of  descent  in 
actual  operation,  because,  forsooth,  fossils  are  necessarily  dead. 
We  can  not  perceive  any  activities,  because  fossils  have  ceased  to 
act.  But,  if  this  doctrine  be  true,  we  should  get  the  series,  if 
there  be  such  a  thing  ;  and  we  do,  as  a  matter  of  fact,  find  longer 
or  shorter  series  of  structures,  series  of  organisms  proceeding  from 
one  form  into  another  form,  which  are  exactly  as  they  ought  to 
be  if  this  process  of  development  by  descent  had  taken  place. 

I  am  careful  to  say  this  ;  because  it  is  literally  true,  as  we  all 
must  admit,  that  species  must  fall  into  some  kind  of  order  or 
other.  You  could  not  collect  bottles,  you  could  not  collect  old 
shoes,  but  you  could  make  some  kind  of  a  serial  order  of  them. 
There  are,  no  doubt,  characters  by  which  such  and  such  shoes 
could  be  distinguished  from  other  shoes,  these  bottles  from  other 
bottles.  But  if  serial  order  does  not  prove  evolution,  as  is  too 
often  assumed,  we  have  in  recent  forms  of  life  in  zoology  and 


PLATE  XIII. 


THE  EXTINCT  MAMMALIA.  30I 

botany,  irrefragable  proofs  of  the  metamorphoses,  and  transfor- 
mations, and  changes  of  the  species,  in  accordance  with  the  doc- 
trine with  which  we  commenced. 

We  now  come  to  the  second  chapter  of  our  subject.  With  the 
assumption,  as  I  take  it  already  satisfactorily  proved,  of  species 
having  changed  into  others,  in  considering  this  matter  of  geo- 
logical succession  or  biological  succession,  I  bring  you  face  to  face 
with  the  nature  and  mode  of  the  change  ;  and  hence  we  may  get 
a  glance  perhaps  at  its  laws. 

I  have  on  the  board  a  sketch  or  table  which  represents  the 
changes  which  took  place  in  certain  of  the  Mammalia.  I  give  you 
a  summary  of  the  kind  of  thing  which  we  find  in  one  of  the 
branches  of  paleontology.  I  have  here  two  figures,  one  represent- 
ing a  restoration,  and  the  other  an  actual  picture,  of  two  extinct 
species  that  belong  to  the  early  Eocene  periods.  One  represents 
the  ancestor  of  the  horse  line,  Hyracotherium,  which  has  four  toes 
on  his  anterior  feet,  and  three  behind  ;  and  the  other  (Plate  XIII) 
a  type  of  animal,  Phenacodus,  which  is  antecedent  to  all  the  horse 
series,  the  elephant  series,  the  hog,  the  rhinoceros,  and  all  the  other 
series  of  hoofed  animals.  It  has  five  toes  on  all  the  feet.  Each 
presents  us  with  the  primitive  position  in  which  their  series  first 
come  to  our  knowledge  in  the  history  of  geological  time. 

I  have  also  arranged  here  a  series  of  some  leading  forms  of  the 
three,  principal  epochs  of  the  Mesozoic  times,  and  six  of  the  lead- 
ing ones  of  the  Tertiary  time.  I  have  added  some  dates  to  show 
you  the  time  when  the  faunae  which  are  entombed  in  those  beds 
were  discovered,  in  the  course  of  our  studies  ;  and  you  will  easily 
see  how  unsafe  it  is  to  say  that  any  given  type  of  life  has  never  ex- 
isted, or  even  to  assert  that  such  and  such  a  form  is  unknown ; 
and  it  is  still  more  unsafe,  I  think,  to  assert  that  any  given  form 
of  life  properly  defined,  or  that  a  specific  intermediate  form  of  life, 
will  not  be  found.  I  think  it  is  much  safer  to  assert  that  such  and 
such  intermediate  forms  will  be  found.  I  have  frequently  had  the 
pleasure  of  realizing  anticipations  of  this  kind.  I  have  asserted 
that  certain  types  would  be  found,  and  they  have  been  found. 
You  will  see  that  I  attend  to  the  matter  of  time  because  there  have 
been  a  great  many  things  discovered  in  the  last  ten  or  fifteen  years 
in  this  department.  With  these  forms  I  give  the  date  of  the  dis- 
covery of  the  fauna  in  which  they  are  embraced. 

Here  we  have  the  White  River  fauna  discovered  in  1856  ;  then 
we  skip  a  considerable  period  of  time,  and  the  next  one  was  in  1869, 


302        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

when  the  Cretaceous  series  was  found.  Six  or  seven  Cretaceous 
faunae  have  been  discovered.  Then  we  have  the  Bridger  fauna  in 
1870,  the  Wasatch  fauna  in  1874.  Next  we  have,  in  1877,  the 
Equus  beds  and  the  fauna  which  they  embrace,  part  of  which  was 
also  found  in  1878.  The  Permian  fauna,  which  is  one  of  the  last, 
in  1879  ;  and  the  latest,  the  Puerco,  which  gives  the  oldest  and 
ancestral  types  of  the  modern  forms  of  Mammalia,  was  only  found 
in  1881.  When  I  first  commenced  the  study  of  this  subject,  about 
1860,  there  were  perhaps  two  hundred  and  fifty  species  known. 
There  are  now  somewhere  above  1,000,  and  we  are  augmenting 
them  all  the  time.  I  have  found  many  myself  :  if  they  were  dis- 
tributed through  the  days  of  the  year,  I  think  in  some  months  I 
should  have  had  several  every  day.  You  see  then  that  the  acces- 
sions to  knowledge  which  are  constantly  being  made  make  it  un- 
safe to  indulge  in  any  prophecies  ;  as,  for  instance,  that,  because 
such  and  such  things  have  not  been  found,  therefore  they  can  not 
be  ;  for  we  find  such  and  such  things  really  have  been  and  really 
are  discovered. 

The  successive  changes  that  we  have  in  the  Mammalia  have 
taken  place  in  the  limbs,  feet,  teeth,  and  brain,  and  the  vertebral 
column.  The  parts  which  present  us  with  the  greatest  numbers 
of  variations  are  those  in  which  many  parts  are  concerned,  as  in 
the  limbs  and  feet.  In  the  Lower  Eocene  (Puerco),  the  toes  were 
5-5.  In  the  Loup  Fork  fauna,  some  possess  toes  but  1-1.  Prior 
to  this  period  no  such  reduction  was  known,  although  in  the  Loup 
Fork  fauna  a  very  few  species  remained  5-5.  Through  this  en- 
tire series  we  have  transitions  steady  and  constant,  from  5-5,  to  4- 
5,  to  4-4,  to  4-3,  to  3-3,  to  2-2,  to  1-1.  In  the  Puerco  period  there 
was  not  a  single  mammal  of  any  kind  which  had  a  good  ankle-joint ; 
which  had  an  ankle-joint  constructed  as  ankle-joints  ought  to  be, 
with  tongue  and  groove.  The  model  ankle-joint  is  a  tongue-and- 
groove  arrangement.  In  this  period  they  were  nearly  all  perfectly 
flat.  As  time  passes  on  we  get  them  more  and  more  grooved,  un- 
til in  the  Loup  Fork  fauna  and  the  White  Eiver  fauna  they  are  near- 
ly all  grooved.  The  soles  of  the  feet,  in  the  Puerco  fauna,  are 
all  flat ;  but  in  the  Loup  Fork  fauna  the  soles  of  the  feet  are  in 
the  air,  and  the  toes  only  are  applied  to  the  ground,  with  the  excep- 
tion of  the  line  of  monkeys,  in  which  the  feet  have  not  become  erect 
on  the  toes,  and  the  elephant,  in  which  the  feet  are  nearly  flat  also, 
and  the  line  of  bears,  where  they  are  also  flat.  As  regards  the 
angulation  between  the  small  bones  of  the  palm  and  of  the  sole, 


THE  EXTINCT  MAMMALIA. 


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304:        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 


tliere  is  not  a  single 
instance  in  which  those 
bones  are  locked  in  the 
Lower  Eocene,  as  they 
are  in  the  later  and 
latest  Tertiary.  So 
also  with  the  articula- 
tion of  the  toes  with 
the  foot. 

When  we  come  to 
the  limbs,  the  species 
of  the  Puerco  fauna 
have  short  legs.  They 
have  gradually  length- 
ened out,  and  in  the 
late  periods  they  are 
nearly  all  relatively 
long. 

Coming  to  the  ver- 
tebrae as  a  part  of  the 
osseous  system,  I  men- 
tion the  zygapoj^hyses, 
or  anteroposteriorly 
directed  processes,  of 
which  the  posterior 
looks  down  and  the  an- 
terior looks  up.  They 
move  on  each  other,  as 
the  vertebral  column 
bends  from  side  to 
side.  In  the  lower 
forms  of  vertebrates 
they  are  always  flat, 
and  in  the  hoofed 
mammals  of  the  Puer- 
co period  they  are  all 
flat.  In  the  Wasatch 
period  we  get  a  single 
group  in  which  the 
articulation,  instead  of 
being  perfectly  flat,  be- 


THE  EXTINCT  MAMMALIA. 


305 


comes  rounded  ;  in  the  later  periods  we  get  them  very  much 
rounded  ;  and,  finally,  in  the  latest  forms,  we  get  the  double 
curve  and  the  locking  process  in  the  vertebral  column,  which, 
as  in  the  limb,  secures  the  greatest  strength  with"  the  greatest 
mobility. 

In  the  first  stages  of  the  growth  of  the  spinal  column,  it  is  a 
notochord,  or  a  cylinder  of  cartilage  or  softer  material.  In  later 
stages  the  bony  deposit  is  made  in  its  sheath  until  it  is  perfectly 
segmented.  Now,  all  the  Permian  land-animals,  reptiles  and 
batrachians,  retain  this  notochord  with  the  elements  of  osseous 
vertebrae,  in  a  greater  or  less  degree  of  completeness.  There  are 
some  in  South  Africa,  I  believe,  in  which  the  ossification  has  come 
clear  through  the  notochord  ;  but  they  are  few.  In  this  charac- 
teristic the  Permian  appears  almost,  perhaps  absolutely,  peculiar  as 


Fig.  61. — Sleeve  of  a  coat  showing  folds  produced  by  lateral  flexure  which  leaves 
interspaces  similar  to  the  segments  of  a  rhachitoraous  vertebra.  Thus,  i  represents  in- 
tercentrum ;  p^  pleuro-centrum  ;  and  w,  neurapophjsis. 

regards  land-animals.  There  is  something  to  be  said  as  to  the  con- 
dition of  the  column  from  a  mechanical  standpoint,  and  it  is  this  : 
that  the  chorda  exists,  with  its  osseous  elements  disposed  about  it  ; 
and  in  the  Permian  batrachians,  equally  related  to  salamanders 
and  frogs,  these  osseous  elements  are  arranged  in  the  sheath  or 
skin  of  the  chorda ;  and  they  are  in  the  form  of  regular  concave 
segments,  very  much  like  such  segments  as  you  can  take  from  the 
skin  of  an  orange — but  parts  of  a  cylinder,  and  having  greater  or 
less  dimensions  according  to  the  group  or  species.  Now,  the  point 
of  divergence  of  these  segments  is  on  the  side  of  the  column.  The 
contacts  are  placed  on  the  side  of  the  column  where  the  segments 
separate — the  upper  segments  rising  and  the  lower  segments  com- 
ing downward.  To  the  upper  segments  are  attached  the  arches 
and  their  articulations,  and  the  lower  segments  are  like  the  seg- 
ments of  a  cylinder.  If  you  take  a  flexible  cylinder,  and  cover  it 
with  a  more  or  less  inflexible  skin  or  sheath,  and  bend  that  cj^linder 

20 


306        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

sidewise,  you  of  course  will  find  that  the  wrinkles  or  fractures  of 
that  part  of  the  surface  will  take  place  along  the  line  of  the 
shortest  curve,  which  is  on  the  side  ;  and,  as  a  matter  of  fact,  you 
have  breaks  of  very  much  the  character  of  the  segments  of  the  Per- 
mian Batrachia.  It  may  not  be  so  symmetrical  as  in  the  actual 
animal,  for  organic  growth  is  symmetrical  so  far  as  not  interfered 
with  ;  for,  when  we  have  two  forces,  the  one  of  hereditary  growth, 
and  the  other  of  change  or  alteration,  and  they  contend,  you  will 
find  in  the  organic  being  a  quite  symmetrical  result.  That  is  the 
universal  rule.  In  the  cylinder  bending  both  ways,  of  course  the 
shortest  line  of  curve  is  right  at  the  center  of  the  side  of  that  C3^1- 
inder,  and  the  longest  curve  is  of  course  at  the  summit  and  base, 
and  the  shortest  curve  will  be  the  point  of  fracture.  And  that  is 
exactly  what  I  presume  has  happened  in  the  case  of  the  construc- 
tion of  the  segments  of  the  sheath  of  the  vertebral  column,  by  the 
lateral  motion  of  the  animal  in  swimming,  and  which  has  been  the 
actual  cause  of  the  disposition  of  the  osseous  material  in  its  form. 
I  have  gone  beyond  the  state  of  the  discussion  in  calling  attention 
to  one  of  the  forces  which  have  probably  produced  this  kind  of 
result.  That  is  the  state  of  the  vertebral  column  of  many  of  the 
Vertebrata  of  the  Permian  period.* 

I  go  back  to  the  Mammalia  and  call  attention  to  the  teeth. 
The  ordinary  tooth  of  the  higher  type  of  the  Mammalia,  whether 
hoofed  or  not,  with  some  exceptions,  is  complex  with  crests  or 
cusps.  By  cutting  the  complex  grinding  surfaces,  we  find  they 
have  been  derived  by  the  infolding  of  .extensions  of  four  original 
cusps  or  tubercles.  They  have  been  flattened,  have  been  rendered 
oblique,  have  run  together,  have  folded  up,  have  become  acute, 
have  descended  deeply,  or  have  lifted  themselves,  so  that  we  have 
teeth  of  all  sorts  and  kinds,  sometimes  very  elegant,  and  often- 

*  Note  (Ed.  1886). — Some  further  elucidation  of  this  point  is  necessary,  since  the 
fishes  have  not  produced  this  kind  of  segmentation  by  the  lateral  motions  of  the 
vertebral  column  in  swimming ;  at  least,  such  segmentation  is  not  yet  known  among 
them,  but  rather  simple  discoidal  segmentation.  The  rhachitomous  segmentation 
above  described  would  result  from  a  greater  flexure  than  that  required  for  the 
propulsion  of  a  fish  through  the  water.  This  increased  flexure  was  no  doubt  the 
concomitant  of  the  acquisition  of  a  terrestrial  mode  of  life  by  the  early  batrachians. 
Progression  on  land  by  an  animal  wnth  weak  limbs  requires  much  greater  flexure  of 
the  column  than  the  act  of  swimming  by  the  use  of  the  caudal  part  of  the  body  as 
in  fishes.  One  can  easily  convince  himself  of  this  by  comparing  the  movements  of 
a  fish  in  the  water  with  those  of  a  salamander  on  land.  The  snakes,  where  limbs 
are  wanting,  show  an  even  stronger  flexure  in  progression. 


THE  EXTINCT  MAMMALIA.  307 

times  yery  effective  in  mechanism.  In  many  primary  ungulates, 
the  primitive  condition  of  four  conical  tubercles  is  found.  In 
passing  to  older  periods  we  find  the  Mammalia  of  the  Puerco 
period,  which  never  have  more  than  three  principal  tubercles, 
with  the  exception  of  three  or  four  species.  In  the  succeeding 
periods,  however,  they  get  the  fourth  tubercle  on  the  posterior 
side.  Finally,  you  get  a  complicated  series  of  grinding  or  cutting 
apparatus,  as  the  case  may  be. 

Last,  but  not  least,  we  take  the  series  of  the  brain.  No  doubt 
the  generalization  is  true,  that  the  primitive  forms  of  Mammalia 
had  small  brains  with  smooth  hemispheres  ;  later  ones  had  larger 
brains  with  complex  hemispheres.  In  general  the  Carnivora  have 
retained  a  more  simple  form  of  brain,  while  herbivorous  animals 
have  retained  a  more  complicated  type  of  brain.  The  lowest 
forms  of  Mammalia  display  the  additional  peculiarity  of  having  the 
middle  brain  exposed  ;  and  the  hemispheres  or  large  lobes  of  the 
brain,  which  are  supposed  to  be  the  seat  of  the  mental  phenomena, 
are  so  reduced  in  size  at  the  back  end,  that  you  see  the  middle 
brain  distinctly,  though  it  is  smaller  than  in  reptiles  and  fishes. 
(See  Plate  XIV. ) 

It  is  beyond  the  possibility  of  controversy,  that  these  series 
have  existed,  that  they  have  originated  in  simj^licity  and  have  re- 
sulted in  complication  ;  and  the  further  induction  must  be  drawn, 
that  the  process  of  succession  has  been  toward  greater  effective- 
ness of  mechanical  work.  There  are  also  cases  of  degradation,  as 
in  the  growing  deficiency  in  dentition  in  man.  There  is  no  doubt 
that  a  large  number  of  people  are  now  losing  their  wisdom-teeth 
in  both  jaws. 

We  are  now  brought  to  the  question  of  the  relations  which 
mind  bears  to  these  principles.  The  question  as  to  the  nature  of 
mind  is  not  so  complex  as  it  might  seem.  There  is  a  great  deal 
of  it,  to  be  sure  ;  but  on  examination  it  resolves  itself  into  a  few 
ultimate  forms.  An  analysis  reduces  it  to  a  few  principal  types  or 
departments — the  departments  of  the  intelligence  and  of  the  emo- 
tions (with  their  primary  simpler  forms,  likes  and  dislikes),  and 
the  will,  if  such  there  be.  These  three  groups,  proposed  by  Kant, 
are  well  known,  and  are  adopted  by  many  metaphysicians  ;  and 
they  stand  the  scrutiny  of  modern  science  as  applied  to  both  men 
and  the  lower  animals.  But  the  question  of  the  material  of  the 
mind,  the  original  raw  stuff  out  of  which  mind  was  made,  is  one 
which  is  claiming  attention  now  from  biologists,  as  it  always  has 


PLATE  XIV. 


a 


a 


Fig.  1. 


Fig.  2. 


Fig.  3.  Fig.  4. 

FiGUBEs  OF  Casts  of  Bratn-Ciiambers  of  Extinct  MAiiMALiA. 

Fig.  1,  Periptychus  rJiahdodon.,  cast  of  roof  of  brain  case,  showing  middle-brain  hemispheres  and 
part  of  olfactory  lobes,  natural  size.  Original ;  from  Puerco  bed  of  New  Mexico.  Fig.  2,  Uinta- 
therium  mirabile^  one  third  natural  size,  from  Marsh.  From  Bridger  bed  of  Wyoming.  Fig.  3, 
Phenacodus  primoevvs^  one  half  natural  size.  Original ;  from  Wasatch  bed  of  Wyoming.  Fig.  4, 
Procamelus  occidentalism  one  half  natural  size.  Original;  from  Loup  Fork  bed  of  New  Mexico. 
Figs,  o,  profile ;  ft,  above ;  c,  below. 


THE  EXTINCT  MAMMALIA,  309 

done  from  physiologists  proper,  and  physicians.  This  is  sensi- 
bility, mere  sim2:)le  sensibility,  unmodified  sensation,  or  con- 
sciousness. Sensibility,  in  connection  with  memory,  is  sufficient 
for  the  accomplishment  of  wonderful  results.  It  is  only  necessary 
to  impress  the  sensibility  with  the  stimuli  which  this  world  affords, 
whether  from  the  outside  or  the  inside,  to  have  the  record  made, 
and  to  have  the  record  kept.  Among  wonderful  things  this  is 
perhaps  the  most  wonderful  :  that  a  given  form  of  matter  should 
be  able  to  retain  a  record  of  events,  a  record  which  is  made  during 
a  greater  or  less  degree  of  sensibility  ;  which  is  retained  in  a  state 
of  insensibility  ;  and  is  finally  returned  to  the  sensibility  by  some 
curious  process  of  adhesion,  as  the  results  of  impresses  which  are 
found  on  the  material  tissue  concerned. 

And  these  simple  elements  of  mind  are  found  in  animals.  No 
zoologist  who  has  perception  or  honesty,  nor  any  farmer  or 
breeder,  nor  any  person  who  has  charge  of  animals  in  any  way, 
can  deny  sensibility  to  all  the  lower  animals  at  times.  The  great 
stumbling-block  in  the  way  of  the  thinker  in  all  this  field,  is  the 
great  evanescence  of  this  sensibility ;  the  great  ease  with  which 
we  dissipate  it.  The  readiness  with  which  we  can  deprive  a  fel- 
low-being of  his  sense  is  a  stumbling-block  in  more  ways  than  one. 
While  it  is  a  question  of  the  greatest  difficulty,  nevertheless,  like 
other  departments  of  nature,  doubtless  it  will  ultimately  be  ex- 
plained by  the  researches  of  physiologists.  I  only  need  to  call  at- 
tention to  consciousness  as  an  important  factor  in  evolution. 

We  now  approach  the  question  of  the  origin  of  organic  ma- 
chines with  fresh  resources.  Did  the  consciousness  of  the  animal 
find  his  structure  made  ready  to  hand,  or  did  he,  under  the  dire 
stimuli  of  necessity,  produce  through  ages  these  modifications  in 
his  own  structure  ?  We  are  told  by  some  of  our  friends  that  law 
implies  a  lawgiver,  that  evolution  implies  an  evolver  :  the  next 
question  is.  Where  is  the  lawgiver  ?  where  is  the  evolver  ?  where 
are  they  located  ?  This  question  is  best  answered,  as  it  appears 
to  me,  as  follows.  In  the  first  place,  I  may  say,  it  is  distinctly 
proved  in  some  directions,  that  the  constant  applications  of  force 
or  motion  in  the  form  of  strains,  in  the  form  of  impacts  and 
blows,  upon  any  given  part  of  the  animal  organism,  do  not  fail  to 
produce  results  in  change  of  structure.  I  believe  the  changes  in 
the  ungulates,  to  which  I  have  called  your  attention,  are  the  re- 
sult of  strains  and  impacts,  precisely  as  I  have  shown  you  the 
manner  of  the  fracture  of  the  vertebral  column  of  the  primitive 


310        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

vertebrates  of  the  Permian  period.  This  would  require  long  dis- 
cussion to  render  clear ;  nevertheless,  I  venture  to  make  the  asser- 
tion that  this  series  of  structures  is  the  result  of  definite  and  dis- 
tinct organic  forces,  directed  to  special  ends.  We  have  yet  to  get 
at  the  conflicting  forces  which  have  produced  the  results  we  see. 
Mechanical  evolution  will  give  us  a  good  deal  to  do  for  some  time 
to  come.  Of  course,  if  motion  has  had  any  effect  in  modifying 
structure,  it  behooves  us  to  investigate  those  conditions  which 
give  origin  to  motion  in  animals.  First  in  order  come  the  sensi- 
bilities of  the  animal,  which  we  have  traced  to  simple  conscious- 
ness ;  and  stimuli,  upon  notice  of  which  he  immediately  begins  to 
move.  The  primary  stimulus  of  all  kinds  of  motion  is  necessarily 
touch.  If  a  stone  falls  upon  the  tail  of  some  animal  which  has 
a  tail,  he  immediately  gets  out  of  that  vicinity.  If  a  jelly-fish 
with  a  stinging  apparatus  runs  across  an  eel  which  has  no  scales, 
the  eel  promptly  moves.  External  applications  of  unpleasant 
bodies  will  always  cause  an  animal  to  chauge  his  location.  Then 
he  is  constantly  assaulted  by  the  dire  enemy  of  beasts,  hunger,  an 
instinct  which  is  evidently  universal,  to  judge  from  the  actions  of 
animals.  This  seems  to  have  fashioned,  in  large  part,  all  forms 
of  life  from  the  least  to  the  greatest,  from  the  most  unorganized  to 
the  most  complex.  Each  exercised  itself  for  the  purpose  of  fill- 
ing its  stomach  with  protoplasm.  Then  come  the  stimuli  which 
appeal  to  a  sense  allied  to  that  of  touch,  changes  of  tempera- 
ture. No  animals  like  to  be  too  cold  or  too  hot ;  and  when  the 
temperature  is  disagreeable,  the  tendency  is  to  go  away  from  that 
locality.  Among  primary  instincts  must  be  included  that  of  re- 
production. After  that  comes  the  sensation  of  resistance,  or, 
carried  to  a  high  degree,  of  anger  :  when  an  animal's  interests  are 
interfered  with,  its  movements  restricted,  the  most  energetic  dis- 
plays are  prompted.  So,  you  see,  it  is  a  matter  of  necessity  that 
mental  phenomena  lie  at  the  back  of  evolution,  provided  always 
that  the  connecting  link  of  the  argument — that  motion  has  ever 
affected  structure — be  true.  That  is  a  point  which,  of  course, 
admits  of  much  discussion.  I  have  placed  myself  on  the  affirm- 
ative side  of  that  question  ;  and,  if  I  live  long  enough,  I  expect  to 
see  it  absolutely  demonstrated. 

Of  course  the  development  of  mind  becomes  possible  under 
such  circumstances.  It  is  not  like  a  man  lifting  himself  up  by 
his  boots,  which  it  would  be  were  there  no  such  thing  as  memory. 
But  with  that  memory  which  accumulates,  which  formulates,  first 


THE   EXTINCT  MAMMALIA.  311 

habits  and  then  structures,  especially  in  the  soft,  delicate  nervous 
tissue,  the  development  of  the  function  of  the  mind,  as  well  as  the 
machinery  of  the  mind,  becomes  perfectly  possible.  We  develop 
our  intellect  through  the  accumulation  of  exact  facts  ;  through 
the  collation  of  pure  truth,  no  matter  whether  it  be  a  humble 
kind  of  truth — as  the  knowledge  of  the  changes  of  the  seasons, 
which  induces  some  animals  to  lay  up  the  winter's  store  ;  whether 
it  be  knowledge  of  the  fact  that  the  sting  of  the  bee  is  very  dis- 
agreeable ;  or  knowledge  of  the  fact  (of  which  the  wild  ox,  no 
doubt,  is  thoroughly  aware)  that  the  teeth  of  the  wolf  are  not 
pleasant  to  come  in  contact  with  ;  or  whether  it  be  the  complex 
knowledge  of  man.  When  the  cerebral  matter  has  become  larger 
and  more  complex,  it  receives  and  retains  a  much  greater  number 
of  impressions,  and  the  animal  becomes  a  more  highly  educated 
being. 

As  regards  the  department  of  emotions  or  passions,  they  are 
also  much  stimulated  by  the  environment.  Animals  which  live  in 
a  state  of  constant  strife,  naturally  have  their  antagonistic  passions 
much  developed  ;  while  amiable,  sympathetic  sentiments  are  better 
and  more  largely  produced  by  peace-loving  animals.  Thus  it  is 
that  the  various  departments  of  the  mind  have  the  beautiful  results 
which  we  now  find  in  the  human  species. 

There  are  some  departments  of  the  mind  which  some  of  our 
friends  decline  to  admit  having  had  such  an  origin.  The  moral 
faculty,  for  instance,  is  excepted  by  many  from  this  series.  But 
the  reasons  why  they  object  to  its  production  in  this  way  are,  to 
my  mind,  not  valid.  The  development  of  the  moral  faculty,  which 
is  essentially  the  sense  of  justice,  appears  to  them  not  to  fall  with- 
in the  scope  of  a  theory  of  descent  or  of  evolution.  It  consists  of 
two  parts.  First  is  the  sentiment  of  benevolence,  or  of  sympathy 
with  mankind,  which  gives  us  the  desire  to  treat  them  as  they 
should  be  treated.  It  is  not  sufficient  for  justice  that  it  is  un- 
mixed mercy  or  benevolence,  which  is  sometimes  very  injurious, 
and  very  often  misplaced.  It  requires,  in  the  second  place,  the 
criticism  of  the  judgment,  of  the  mature  intellect,  of  the  rational 
faculty,  to  enable  the  possessor  to  dispose  of  his  sentiments  in  the 
proper  manner.  The  combination  of  rational  discrimination  and 
judgment,  with  benevolence,  constitutes  the  sense  of  justice,  which 
has  been  derived,  no  doubt,  as  a  summary  of  the  development  of 
those  two  departments  of  the  mind — the  emotions  and  the  intel- 
lect. 


312        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

It  is  said  that  a  sense  of  justice  could  not  be  derived  from 
no  sense  of  justice  ;  that  it  could  not  have  been  derived  from  the 
state  of  things  which  we  find  in  the  animals,  because  no  animal  is 
known  to  exhibit  real  justice ;  and  that  objection  is  valid  as  far 
as  it  goes.  1  suspect  that  no  animal  has  been  observed  to  show  a 
true  sense  of  justice.  That  they  show  sympathy  and  kindness, 
there  is  no  question  ;  but  when  it  comes  to  real  justice,  they  do 
not  display  it.  But  do  all  men  display  justice  ?  Do  all  men 
understand  justice  ?  I  am  very  sure  not.  There  are  a  good  many 
men  in  civilized  communities,  and  there  are  many  tribes,  who  do 
not  know  what  justice  is.  It  does  not  exist  as  a  part  of  every 
mental  constitution.  I  never  lived  among  the  Bushmen,  and  do 
not  know  exactly  what  their  mental  constitution  is  ;  but  in  a  gen- 
eral way  the  justice  of  savages  is  restricted  to  the  very  smallest 
possible  circle — that  of  their  tribe  or  of  their  own  family.  There 
is  a  class  of  people  who  do  not  understand  justice.  I  do  not  refer 
to  people  who  know  what  right  is,  and  do  not  do  it ;  but  to  the 
primitive  state  of  moral  character,  in  which,  as  in  children,  true 
justice  is  unknown.  I  call  attention  to  the  fact,  because  some 
of  our  friends  have  been  very  much  afraid  that  the  demonstration 
of  the  law  of  evolution,  physical  and  metaphysical,  would  result 
in  danger  to  society.  I  suspect  not.  The  mode  in  which  I  under- 
stand this  question  appears  to  me  to  be  beneficial  to  society,  rather 
than  injurious  ;  and  I  therefore  take  the  liberty  of  appending  this 
part  of  the  subject  to  its  more  material  aspect. 

I  refer  to  another  topic,  that  is  to  the  nature  of  life,  and  the 
physical  basis  of  life.  The  word  '*  life  "  is  so  complex  that  it  is 
necessary  to  define  it,  and  so  to  define  it  away  that  really  the  word 
"life"  does  not  retain  its  usual  definition.  Many  phenomena  of 
life  are  chemical,  physical,  mechanical.  We  have  to  remove  all 
these  from  consideration,  because  they  come  within  the  ordinary 
laws  of  mechanical  forces  ;  but  we  have  a  few  things  left  which 
are  of  a  different  character.  One  is  the  law  of  growth,  which  is 
displayed  in  the  processes  of  embryonic  succession  ;  secondly,  the 
wonderful  phenomena  of  sensibility.  Those  two  things  we  have 
not  yet  reduced  to  any  identity  with  the  ordinary  laws  of  force, 
though  we  know  of  their  dynamic  equivalency.  In  the  phenome- 
na of  embryology  the  phenomena  of  evolution  are  repeated,  only 
concentrated  in  the  early  stages  through  which  animals  have  to 
pass.  So  whatever  explains  the  general  phenomena  of  evolution 
explains  the  phenomena  of  embryology. 


THE  EXXmCT  MAMMALIA.  3I3 

What  is  the  nature  of  physical  sensibility  ?  In  this  planet,  it 
is  found  residing  only  in  one  form  of  matter,  which  has  a  slightly 
varied  chemical  constitution,  namely,  protoplasm,  so  called  from 
a  physical  standpoint.  Now,  this  world,  as  3'ou  all  know,  has 
passed  through  many  changes  of  temperature.  Its  early  periods, 
it  is  probable,  were  so  very  hot  that  protoplasm  had  a  very  poor 
chance.  Again,  can  we  assume  for  a  moment  that  this  little  speck 
in  the  great  universe  is  the  only  seat  of  life  ?  I  suppose  scarcely 
any  scientific  man  will  venture  to  do  so.  If,  therefore,  life  exists 
in  other  planets,  worlds,  and  systems,  does  it  necessarily  occupy 
bodies  of  protoplasm  in  those  different,  remote,  spheres  ?  It  would 
be  a  great  assumption.  It  is  altogether  improbable.  The  cer- 
tainty is,  that  in  those  planets  which  are  in  proximity  to  the  sun's 
heat  there  could  be  no  protoplasm.  Protoplasm  in  the  remote 
planets  would  be  a  hard  mineral,  and  near  the  sun  it  would  be  dis- 
sipated into  its  component  gases.  So  that,  if  life  be  found  in  other 
parts  of  this  universe,  it  must  reside  in  some  different  kind  of 
material.  It  is  extremely  probable  that  the  physical  conditions 
that  reside  in  protoplasm  might  be  found  in  other  kinds  of  matter. 
It  is  in  its  chemical  inertness,  and  in  its  physical  constitution,  that 
its  adaptation  to  life  resides  ;  and  the  physical  constitution  neces- 
sary for  the  sustentation  of  life  may  be  well  supposed  to  exist  in 
matter  in  other  parts  of  the  universe.  I  only  say  the  door  is  open 
and  not  closed  :  any  one  who  asserts  that  life  can  not  exist  in  any 
other  material  basis  than  protoplasm  is  assuming  more  than  the 
world  of  science  will  permit  him  to  assume.  And  that  it  is  con- 
fined to  this  single  planet,  among  the  great  systems  of  the  universe 
— that  assumption  will  not  for  a  moment  be  allowed.  Therefore 
the  subject  is  one  which  allows  us  a  free  field  for  future  investiga- 
tion :  it  is  by  no  means  closed  in  the  most  important  laws  which 
it  presents  to  the  rational  thinker.  I  hope,  also,  if  the  evi- 
dence in  favor  of  this  hypothesis  of  .the  creation  of  living  forms 
be  regarded  as  true,  that  no  one  will  find  in  it  any  ground  for  any 
very  serious  modification  of  existing  ideas  on  the  great  questions  of 
right  and  wrong,  which  have  been  long  since  known  by  men  as  a 
result  of  experience,  and  without  any  other  scientific  demonstra- 
tion whatsoever. 


XI. 

ON  THE  EVOLUTION  OF  THE  VERTEBRATA,  PRO- 
GRESSIVE AND  RETROGRESSIVE. 

I.    PRELIMINARY. 

IisT  attempting  to  ascertain  the  course  of  evolution  of  the 
Vertebrata,  and  to  construct  phylogenetic  diagrams  which  shall 
express  this  history,  among  the  difficulties  arising  from  deficient 
information  one  is  especially  prominent.  As  is  well  known, 
there  are  many  types  in  all  the  orders  of  the  Vertebrata  which 
present  us  with  rudimentary  organs,  as  rudimental  digits,  feet  or 
limbs,  rudimental  fins,  teeth,  and  wings.  There  is  scarcely  an 
organ  or  part  which  is  not  somewhere  in  a  rudimental  and  more 
or  less  useless  condition.  The  difficulty  which  these  cases  present 
is,  simply,  whether  they  be  persistent  primitive  conditions,  to  be 
regarded  as  ancestral  types  which  have  survived  to  the  present 
time,  or  whether,  on  the  other  hand,  they  be  results  of  a  pi'ocess 
of  degeneration,  and  therefore  of  comparatively  modern  origin. 
The  question,  in  brief,  is,  whether  these  creatures  presenting 
these  features  be  primitive  ancestors  or  degenerate  descendants. 

In  the  first  place,  let  us  define  the  meaning  of  the  word  degen- 
erate. This  must  be  done  first  from  a  structural  or  anatomical 
standpoint.  Degeneracy  may  be  defined  as  a  loss  of  parts  with- 
out corresponding  development  of  other  f>ai'ts.  All  animals  are 
degenerate  in  some  respect  or  another,  as,  for  instance,  the  Mam- 
malia in  the  small  size  of  the  pineal  gland  and  of  the  coracoid 
bone  ;  so  that  degeneracy,  as  a  whole,  can  only  be  affirmed  where 
the  sum  of  the  subtractions  is  greater  than  the  sum  of  the  addi- 
tions. Function  of  the  parts  must,  however,  be  consulted  in  this 
matter.  We  naturally  regard  sensibility  as  the  highest  of  animal 
functions,  and  mind  as  the  highest  form  of  sensibility.  There- 
fore development  of  organs  of  sensibility  and  sense  and  mind,  con- 
stitutes a  better  claim  of  progress  than  development  of  stomach 
or  of  skin.     Since  motion  is  under  the  direction  of  sensibility, 


EVOLrXION   OF  THE   VERTEBRATA.  315 

organs  of  movement  have  much  to  do  with  the  question.  When 
perfection  in  this  respect  conflicts  with  perfection  of  brain,  in 
evidence  of  position,  we  naturally  give  the  preference  to  the 
latter  in  deciding.  Thus  the  ruminating  mammals  are  much 
superior  to  man  in  the  structure  of  their  feet,  teeth,  and  stomach, 
yet  we  properly  assign  the  higher  position  to  the  Quadrumana  and 
to  man,  on  account  of  the  superior  complication  of  their  brain- 
structure. 

Paleontology  has  proved,*  what  had  been  already  surmised, 
that  the  development  of  animal  organisms  has  been  on  lines  of 
increasing  specialization  of  parts.  That  is,  in  lines  of  increas- 
ingly perfect  adaptations  of  structures  to  ends,  or  functions.  In 
certain  series  of  animals  we  witness  steadily  increasing  perfection 
of  mechanisms  of  the  limbs  for  running  ;  in  others  for  digging  ; 
in  others  for  flying.  In  the  teeth  we  find  increasing  perfection  of 
machines  for  grinding,  for  cutting,  or  for  seizing.  In  the  brain 
the  specialization  has  evidently  been  toward  increased  acuteness 
of  perception,  increased  energy  of  action,  and  increased  intelli- 
gence. Specialization  does  not,  however,  necessarily  imply  pro- 
gressive development.  Adaptation  may  be  to  a  parasitic  or  a  ses- 
sile mode  of  life.  Such  adaptation  is  often  displayed  in  a  very 
special  modification  of  parts,  as  in  the  anterior  limbs  of  some  of 
the  parasitic  Crustacea ;  in  the  mouth  parts  of  some  Arachnida ; 
in  the  feet  of  the  sloth,  and  in  the  jaws  of  the  ant-eaters. 

Embryology  has  furnished,  and  will  furnish,  many  important 
hints  and  demonstrations  as  to  the  true  meaning  of  the  rudiment- 
ary condition  or  absence  of  parts,  and  thus  indicate  the  phylo- 
genetic  connections  of  animals.  Thus  the  origin  of  the  Tunicata 
from  primitive  vertebrate-like  forms  would  probably  never  have 
been  suspected  but  for  embryological  studies ;  and  the  origin  of 
the  very  peculiar  order  of  Eotifera  has  been  explained  in  like 
manner.  But  embryology  has  its  limitations,  for  the  transitional 
characters  presented  by  embryos  are  only  partially  of  the  nature 
of  a  record  of  the  structures  which  belonged  to  their  ancestors  in 
successive  geological  ages,  and  are  frequently  special  adaptations 
to  the  necessities  of  their  embryonic  life.  Such  are  the  stato- 
blasts  which  are  present  in  fresh-water  sponges  and  Polyzoa,  and 
wanting  in  the  marine  forms  ;  and  the  allantois  and  placenta  of 

*  Cfr.  "  On  the  Evidence  for  Evolution  in  the  History  of  the  Extinct  Mam- 
malia," "Proc.  Amer.  Assoc.  Adv.  Sciences"  for  1883. 


316        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

Vertebrata.  In  a  number  of  groups  the  embrj^o  seems  to  have 
been  more  susceptible  to  the  influence  of  the  environment  than 
the  adults.*  It  results  that  in  many  cases  the  phylogeny  can 
only  be  determined  by  the  discovery  and  investigation  of  the 
ancestors  themselves,  as  they  are  preserved  in  the  crust  of  the 
earth.  In  all  cases  this  discovery  confirms  and  establishes  such 
definite  conclusions  as  may  be  derived  from  embryology.  It  is 
also  clear  that  on  the  discovery  of  phylogenetic  series  it  becomes 
at  once  possible  to  determine  the  nature  of  defective  types.  It 
becomes  possible  to  ascertain  whether  their  rudimental  parts 
represent  the  beginnings  of  organs,  or  whether  they  are  the 
.result  of  a  process  of  degeneration  of  organs  once  well  develoj^ed. 
A  great  deal  of  light  has  been  happily  thrown  on  this  question, 
as  regards  the  Vertebrata,  by  the  recent  work  done  in  North 
American  paleontology.  The  lines  of  descent  of  many  of  the 
minor  groups  have  been  positively  determined,  and  the  phyloge- 
netic connections  of  most  of  the  primary  divisions  or  classes  have 
been  made  out.     The  result  of  these  investigations  has  been  to 

*  A  remarkable  instance  of  this  state  of  things  appears  in  the  history  of  the 
evolution  of  the  insects.  It  is  quite  impossible  to  understand  this  history  without 
believing  that  the  larval  and  pupal  states  of  the  highest  insects  are  the  results  of  a 
process  of  degeneracy  which  has  affected  the  middle  periods  of  growth  but  not  the 
mature  results.  The  earliest  insects  are  the  Orthoptera,  which  have  active  aggres- 
sive larvae  and  pupae,  undergoing  the  least  changes  in  their  metamorphosis  (Ameta- 
bola),  and  never  getting  beyond  the  primitive  mandibulate  condition  at  the  end. 
The  metamorphosis  of  the  jawed  Neuroptera  is  little  more  marked,  and  they  are 
one  of  the  oldest  orders. 

The  highest  orders  with  jaws  undergo  a  marked  metamorphosis  (Coleoptera, 
Hymenoptera),  the  Hymenoptera  even  requiring  artificial  intervention  in  some  in- 
stances to  make  it  successful.  Finally,  the  most  specialized  orders,  the  suctorial 
Diptera  and  Lepidoptera,  especially  the  latter,  present  us  with  very  unprotected 
more  or  less  parasitic  stages,  both  active  and  inactive.  These  animals  have 
evidently  degenerated,  but  not  so  as  to  prevent  their  completing  a  metamorphosis 
necessary  for  purposes  of  reproduction.  As  is  well  known,  many  imagines  (Satur- 
niidae,  (Estridae)  can  perform  no  other  function,  and  soon  die,  while  in  some  Diptera 
the  incomplete  larvae  themselves  reproduce,  so  that  the  metamorphosis  is  never 
completed. 

This  history  is  parallel  to  that  proposed  by  Dohrn  to  account  for  the  origin  of 
the  Amraocoetes  larval  stage  of  the  Marsipobranchii.  He  supposes  this  form  to  be 
more  degenerate  than  its  probable  ancestral  type  in  the  ancestral  line  of  the  Verte- 
brata, as  it  is  inferior  to  its  own  adult.  An  inactive  life  in  mud  is  supposed  by 
Dohrn  to  have  been  the  effective  cause.  An  inactive  life  on  the  leaves  of  plants, 
or  in  dead  carcases,  has  probably  been  the  cause  of  the  same  phenomenon  in  the 
Lepidoptera  and  Diptera. 


EVOLUTION   OF  THE   VERTEBRATA.  317 

prove  that  the  evolution  of  the  Vertebrata  has  proceeded  not  only 
on  lines  of  acceleration,  but,  to  a  much  greater  extent  than  has 
been  heretofore  suspected,  on  lines  of  retardation.*  That  is,  that 
evolution  has  been  not  only  progressive,  but  at  times  retrogressive. 
This  is  entirely  in  accord  with  the  views  derived  by  Dohrn  from 
embryology,!  who,  however,  wrote  only  of  the  origin  of  the 
Vertebrata  as  a  whole  and  not  of  its  divisions,  excepting  only 
the  Leptocardii  and  Marsipobranchii,  that  is,  of  the  sand-lance 
and  the  lampreys  and  hags.  The  demonstration  of  such  relations 
for  the  higher  Vertebrata  is  now  done  nearly  for  the  first  time.  J 

Omitting  from  consideration  the  two  classes  above  mentioned, 
whose  remains  have  not  yet  been  certainly  found  in  a  fossil  state, 
there  remain  the  following  :  the  Pisces,  Batrachia,  Eeptilia,  Aves, 
and  Mammalia. 

The  Mammalia  have  been  traced  to  the  theromorphous  reptiles 
through  the  Monotremata.  The  birds,  some  of  them  at  least,  ap- 
pear to  have  been  derived  from  the  Dinosaurian  reptiles.  The  rep- 
tiles, in  their  primary  representative  order,  the  Theromorpha,  have 
been  probably  derived  from  the  rhachitomous  Batrachia.*  The 
Batrachia  have  originated  from  the  subclass  of  fishes,  the  Dipnoi, 
though  not  from  any  known  form.  I  have  shown  that  the  true 
fishes  or  Teleostomi  have  descended  from  an  order  of  sharks,  || 
the  Ichthyotomi,  which  possess  characters  of  the  Dipnoi  also. 
The  origin  of  the  sharks  remains  entirely  obscure,  as  does  also 
that   of  the   Pisces   as  a  whole.      Dohrn  believes  the  Marsii^o- 

*  See  "Origin  of  Genera,"  E.  D.  Cope,  Philadelphia,  1868,  where  these  terms 
are  introduced. 

f  See  "Der  Ursprung  der  Wirbelthiere  u.  d.  Princip  des  Functionwechsels," 
Leipsic,  18'75. 

^  "On  the  Phylogeny  of  the  Vertebrata,"  Cope,  "  Amer.  Naturalist,"  Dec.,  1884. 
I  here  remark  that  my  researches  have  now,  as  I  believe,  disclosed  the  ancestry  of 
the  mammals,  the  birds,  the  reptiles,  and  the  true  fishes,  or  Teleostomi,  including 
the  special  phylogenies  of  the  Batrachia  and  Reptilia,  and  some  of  the  Mammalia. 
See  the  following  references:  "American  Naturalist,"  1884,  p.  1136  ;  "Proceedings 
Academy  Philadelphia,"  186Y,  p.  234;  "Proceedings  American  Philosoph.  Society," 
1884,  p.  585;  "American  Naturalist,"  1884,  p.  27;  "Proceedings  American  Asso- 
ciation for  the  Advancement  of  Science,"  xix,  ISTl,  p.  233;  "Proceedings  Amer- 
ican Philosophical  Society,"  1882,  p.  447;  "American  Naturalist,"  1884,  pp.  261 
and  1121  ;  "Report  U.  S.  Geol.  Survey  W.  of  lOOth  Mer.,"  G.  M.  Wheeler,  1877, 
iv,  ii,  p.  282. 

*  Through  the  batrachian  order  Embolomeri.     (Ed.  1886.) 
I  "Proceedings  Am.  Phil.  Soc,"  1884,  p.  585. 


318        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTIOi^. 

branchii  to  have  acquired  its  present  characters  by  a  process  of 
degeneration.  The  origin  of  the  Vertebrata  is  as  yet  entirely  un- 
known, Kowalevsky  deriving  them  from  the  Ascidians,  and 
Semper  from  the  Annelida.  The  above  results  I  have  embodied 
in  the  following  phylogenetic  diagram  : 

Aves        Mammalia 

\  / 

\  / 

Reptilia 

/ 
/ 

[  Teleostomi*        Batrachia 

I  I  ^  ■ 

Pisces      \       Selachii  Ichthjotorai  Dipnoi 


Holocephali 
Leptocardii 


Marsipobranchi 


Accepting  this  phylogeny,  it  becomes  possible  to  determine 
the  course  of  development,  first,  of  the  whole  series  ;  and,  secondly, 
of  the  contents  of  each  class  taken  by  itself.  I  will  first  consider 
the  direction  of  the  evolution  of  the  Vertebrata  as  a  whole. 

IT.    THE   VERTEBRATE    LINE. 

The  Vertebrata  exhibit  the  most  unmistakable  gradation  in 
the  characters  of  the  circulatory  system,  f  It  has  long  been  the 
custom  to  define  the  classes  by  means  of  these  characters,  taken 
in  connection  with  those  of  the  skeleton.  Commencing  in  the 
Leptocardii  with  the  simple  tube,  we  have  two  chambers  in  the 
Marsipobranchii  and  fishes  ;  three  in  the  Batrachia  and  Reptilia  ; 
and  four  in  the  Aves  and  Mammalia.  The  aorta-roots  commence 
as  numerous  pairs  of  branchial  arteries  in  the  Leptocardii ;  we 
see  seven  in  the  Marsipobranchi,  five  in  the  fishes  (with  number 
reduced  in  some)  ;  four  and  three  in  Batrachia,  where  they  gener- 
ally cease  to  perform  branchial  functions  ;  two  and  one  on  each 
side  in  Reptilia ;  the  right-hand  one  in  birds,  and  the  left-hand 
one  in  Mammalia.  This  order  is  clearly  an  ascending  one  through- 
out. It  consists  of,  first,  a  transition  from  adaptation  to  an  aquatic, 
to  an  aerial  respiration  ;  and,  second,  an  increase  in  the  power  to 
aerate  and  distribute  a  circulating  fluid  of  increased  quantity, 

*  In  the  original  I  used  the  name  Hyopomata  for  this  division,  but  Owen's  name 
Teleostomi  is  prior.     (Ed.  1886.) 

+  See  *'  Origin  of  Genera/'  1868,  p.  20,  for  a  table  of  the  characters  of  the  circu- 
latory system. 


EVOLUTION   OF  THE   YERTEBRATA.  319 

and  of  increased  calorific  capacity.  In  other  words,  the  circula- 
tion passes  from  the  cold  to  the  hot  blooded  type  coincidentally 
with  the  changes  of  structure  above  enumerated.  The  accession 
of  a  capacity  to  maintain  a  fixed  temperature  while  that  of  the 
surrounding  medium  changes,  is  an  important  advance  in  animal 
economy. 

The  brain  and  nervous  system  also  display  a  general  progress- 
ive ascent.  Leaving  the  brainless  Leptocardii,  the  Marsipo- 
branchs  and  fishes  present  us  with  small  hemispheres,  larger 
optic  lobes,  and  well-developed  cerebellum.  The  hemispheres 
are  really  larger  than  they  appear  to  be,  as  Rabl  Riickard  has 
shown  *  that  the  supposed  hemispheres  are  only  corpora  striata. 
But  the  superior  walls  are  membranous,  and  sujoport  on  their  in- 
ternal side  only  a  layer  of  epithelial  cells,  as  in  the  embryos  of 
other  Vertebrata,  instead  of  the  gray  substance.  So  that,  al- 
though we  find  that  the  cerebellum  is  really  smaller  in  the 
Batrachia  and  most  Eeptilia  than  in  the  fishes,  the  better  de- 
velopment of  the  hemispheres  in  the  former  gives  them  the  pre- 
eminence. The  Elasmobranchii  show  themselves  superior  to 
many  of  the  fishes  in  the  large  size  of  their  corpora  restiformia 
and  cerebellum.  The  Eeptilia  constitute  an  advance  on  the  Ba- 
trachia. In  the  latter  the  optic  thalami  are,  with  some  excep- 
tions, of  greater  diameter  than  the  hemispheres,  while  the  reverse 
is  generally  true  of  the  reptiles.  The  crocodiles  display  much 
superiority  over  the  other  reptiles  in  the  larger  cerebellum,  with 
rudimental  lateral  lobes.  The  great  development  of  the  hemi- 
spheres in  birds  is  well  known,  while  the  general  superiority  of 
the  brain  of  the  living  Mammalia  over  all  other  vertebrates  is 
admitted. 

The  consideration  of  the  successive  relations  of  the  skeleton  in 
the  classes  of  vertebrates  embraces,  of  course,  only  the  characters 
which  distinguish  those  classes.  These  are  not  numerous.  They 
embrace  the  structure  of  the  axis  of  the  skull ;  of  the  ear-bones  ; 
of  the  suspensors  of  the  lower  jaw  ;  of  the  scapular  arch  and 
anterior  limb,  and  of  the  pelvic  arch  and  posterior  limb.  Other 
characters  are  numerous,  but  do  not  enter  into  consideration  at 
this  time. 

The  persistence  of  the  primitive  cartilage  in  any  part  of  the 
skeleton   is,    embryologically   speaking,    a   mark    of    inferiority. 


*  n 


Biologisches  Centralblatt,"  1884,  p.  449. 


320        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

From  a  physiological  or  functional  standpoint  it  has  the  same 
significance,  since  it  is  far  less  effective  both  for  support  and  for 
movement  than  is  the  segmented  osseous  skeleton.  That  this  is 
a  prevalent  condition  of  the  lower  Vertebrata  is  well  known. 
The  bony  fishes  and  Batrachia  have  but  little  of  the  primitive 
cartilage  remaining,  and  the  quantity  is  still  more  reduced  in  the 
higher  classes.  Systematically,  then,  the  vertebrate  series  is  in 
this  respect  an  ascending  one.  The  Leptocardii  are  membra- 
nous ;  the  Marsipobranchii  and  most  of  the  Elasmobranchii 
cartihiginous ;  the  other  Pisces  and  the  Batrachia  have  tlie 
basicranial  axis  cartilaginous,  so  that  it  is  not  until  the  Eeptilia 
are  reached  that  we  have  osseous  sphenoid  and  presphenoid  bones, 
such  as  characterize  the  birds  and  mammals.  The  vertebral 
column  follows  more  or  less  inexactly  the  history  of  the  base  of 
the  skull,  but  its  characters  do  not  define  the  classes. 

As  regards  the  suspensor  of  the  lower  jaw,  the  scale  is  in  the 
main  ascending.  We  witness  a  gradual  change  in  the  segmenta- 
tion of  the  mandibular  visceral  arch  of  the  skull,  which  clearly 
has  for  its  object  such  a  concentration  of  the  parts  as  will  produce 
the  greatest  effectiveness  of  the  biting  function.  This  is  accom- 
plished by  reducing  the  number  of  the  segments,  so  as  to  bring 
the  resistance  of  the  teeth  nearer  and  nearer  to  the  power,  that  is, 
the  masse ter  and  related  muscles,  and  their  base  of  attachment, 
the  brain-case.  This  is  seen  in  bony  Vertebrates  in  the  reduction 
of  the  segments  between  the  lower  jaw  proper  and  the  skull,  from 
four  to  none.  In  the  fishes  we  have  the  hyomandibular,  the  sym- 
plectic,  the  inferior  quadrate,  and  the  articular.  In  the  Ba- 
trachia, reptiles  and  birds,  we  have  the  quadrate  and  articular 
only,  while  in  the  Mammalia  these  elements  also  are  wanting. 

The  examination  of  the  pectoral  and  pelvic  arches  reveals  a 
successive  modification  of  the  adaptation  of  the  parts  to  the  me- 
chanical needs  of  the  limbs.  In  this  regard  the  air-breathing 
types  display  wide  diversity  from  the  gill-bearing  types  or  fishes. 
In  the  latter,  the  lateral  elements  unite  below  without  the  inter- 
vention of  a  median  element  or  sternum,  while  in  the  former  the 
sternum,  or  parts  of  it,  is  generally  present.  Either  arrange- 
ment is  susceptible  of  much  mechanical  strength,  as  witness  the 
Siluroid  fishes  on  the  one  hand,  and  the  mole  on  the  other.  The 
numerous  segments  of  the  fishes'  pectoral  arch  must,  however,  be 
an  element  of  weakness,  so  that  from  a  mechanical  standpoint  it 
must  take  the  lowest  place.     The  presence  of  sternal  elements, 


EVOLUTION   OF  THE  VERTEBRATA.  321 

with  both  clavicle,  procoracoid,  and  coracoid  bones  on  each  side, 
gives  the  Reptilia  the  highest  place  for  mechanical  strength.  The 
loss  of  the  coracoid  seen  in  the  tailed  Batrachia,  and  loss  of  cora- 
coid and  procoracoid  in  the  Mammalia,  constitute  an  element  of 
weakness.  The  line  is  not  then  one  of  uniform  ascent  in  this  re- 
spect. 

The  absence  of  pelvis,  or  its  extremely  rudimental  condition  in 
fishes,  places  them  at  the  foot  of  the  line  in  this  respect.  The 
forward  extension  of  the  ilium  in  some  Batrachia  and  in  the  Mam- 
malia, is  to  be  compared  with  its  backward  direction  in  Reptilia, 
and  its  extension  both  ways  in  the  birds.  These  conditions  are 
all  derived  by  descent  from  a  strictly  intermediate  position  in  the 
Batrachia  and  Reptilia  of  the  Permian  epoch.  The  anterior  di- 
rection must  be  regarded  as  having  the  mechanical  advantage 
over  the  posterior  direction,  since  it  shortens  the  vertebral  column 
and  brings  the  posterior  nearer  to  the  anterior  feet.  The  prev- 
alence of  the  latter  condition  in  the  Mammalia  enables  them  to 
stand  clear  of  the  ground,  while  the  Reptilia  move  with  the  abdo- 
men resting  upon  it.  As  regards  the  inferior  arches  of  the  pelvis, 
the  Mammalia  have  the  advantage  again,  in  the  strong  bony  me- 
dian symphysis  connecting  the  ischium  and  pubis.*  This  char- 
acter, universal  among  the  land  Vertebrata  of  the  Permian  epoch, 
has  been  lost  by  the  modern  Reptilia,  and  birds,  and  is  retained 
only  by  the  Mammalia.  So  the  lines,  excepting  the  mammalian, 
have  degenerated  in  every  direction  in  the  characters  of  the  pelvis. 

The  limbs  of  the  Pisces  are  as  well  adapted  to  their  environ- 
ment as  are  those  of  the  land  Vertebrata  ;  but,  from  an  embryolog- 
ical  standpoint,  their  structure  is  inferior.  The  primitive  raj^s 
are  less  modified  in  the  fin  than  in  the  limb  ;  and  limbs  them- 
selves display  a  constantly  increasing  differentiation  of  parts,  com- 
mencing with  the  Batrachia  and  ending  with  the  Mammalia. 
The  details  of  these  modifications  belong  to  the  history  of  the 
contents  of  the  classes,  however,  rather  than  to  the  succession  of 
the  Vertebrata  as  a  whole. 

In  review,  it  may  be  said  that  a  comparison  of  the  characters 
which  define  the  classes  of  the  Vertebrates  shows  that  this  branch 
of  the  animal  kingdom  has  made  with  the  ages  successive  steps 
of  progress  from  lower  to  higher  conditions.  This  progress  has 
not  been  without  exception,  since,  as  regards  the  construction  of 

*  This  is  an  advantage  as  a  protection  during  gestation. 
21 


322        THE  STRUCTURAL  EVIDENCE  OF  EVOLUTIOK 

the  scapular  arch,  the  Mammalia  have  retrograded  from  the  rep- 
tilian standard  as  a  Avhole. 

In  subsequent  pages  I  shall  take  up  the  lines  of  the  classes 
separately. 

III.    THE   LliTE   OF   THE   UKOCHOKDA. 

Embryological  evidence  leads  us  to  anticipate  that  the  primi- 
tive Vertebrata  possessed  nothing  representative  of  the  vertebrate 
skeleton  beyond  a  chorda  dorsalis.  Above  this  axis  should  lie  the 
nervous  chord,  and  below  it  the  nutritive  and  reproductive  sys- 
tems and  their  appendages.  Such  a  type  we  have  in  its  simplest 
form  in  the  Branchiostoma,  the  representative  of  the  division  of 
the  Acrania.  In  the  animals  of  this  division  the  mouth  and  anus 
have  the  usual  vertebrate  jDosition,  at  opposite  ends  of  the  body- 
cavity.  The  Tunicata  (formerly  referred  to  the  Mollusca)  are  now 
known  to  present  a  still  more  primitive  type  of  Vertebrata,  to 
which  the  name  of  Urochorda  has  been  given.  These  curious, 
frequently  sessile  creatures,  have  a  vertebrate  structure  during  the 
larval  stage,  which  they  ultimately  lose.  They  have  the  necessary 
chorda,  and  nervous  axis  with  a  brain,  and  a  cerebral  eye.  They 
have  at  this  time  a  tail>  and  are  free-swimming ;  a  peculiarity 
which  a  few  of  them  retain  throughout  life  (Appendicularia).* 
They  differ  from  the  Acrania  in  the  positions  of  the  extremities 
of  the  alimentary  canal.  The  mouth  is  on  the  top  of  the  anterior 
end  of  the  animal,  and  is  supposed  by  some  anatomists  to  repre- 
sent an  open  extremity  of  the  pineal  gland  of  other  Vertebrata ; 
while  the  tract  represented  by  this  body,  the  third  ventricle  of  the 
brain,  and  the  pituitary  body  of  the  Craniata,  are  the  remains  of 
the  primitive  oesophagus  of  the  Urochorda.  The  anus  in  the 
adult  tunicates  is  either  dorsal,  or  it  opens  into  the  body-cavity,  as 
in  the  young  larvas.     In  Appendicularia  it  is  ventral  (Gegenbaur). 

The  history  of  the  Tunicata  can  not  be  traced  by  paleontolo- 
gists as  yet,  owing  to  the  absence  of  hard  parts  in  their  structure. 
The  evidence  of  embryology  has,  however,  convinced  phylogenists 
that  the  ancestors  of  this  class  resembled  their  larvae,  and  that  they 
have  as  a  whole  undergone  a  remarkable  degeneracy.  They  have 
passed  from  an  active,  free  life  to  a  sessile  one,  and  have  lost  the 
characters  which  pertain  to  the  life  of  vertebrates  generally. 

It  was  to  have  been  anticipated,  however,  that  all  of  these  an- 


*  See  Lankester  on  "Degeneration,"  "  Nature  Series,"  1880. 


EVOLUTION   OF  THE   VERTEBRATA. 


323 


cestral  Tunicata  did  not  undergo  this  degenerative  metamorphosis 
for  it  is  to  such  types  that  we  must  look  for  the  ancestors  of  the 
other  Vertebrata,  the  Acrania  and  the  Craniata.  And  here  pale- 
ontology steps  in  and  throws  new  light  on  the  question.  I  have 
pointed  out  briefly,  in  the  "  American  Naturalist/'  *  that  a  second 
order  must  be  added  to  the  Urochorda,  viz.,  the  Antiarcha,  in 
which  the  anus  presents  the  same  position  as  in  the  Acrania,  at 
the  posterior  end  of  the  body,  while  an  orifice  of  the  upper  surface 
represents  the  mouth  of  the  Tunicata.  To  this  order  is  to  be  re- 
ferred the  family  of  the  Pterichthyidag,  of  which  the  typical  genus, 


Fig.  63. 


Fig.  62. 

Fig.  62.  Bothriolepis  canadensis  Whiteaves,  from  above,  half  size  of  a  small  speci- 
men. The  valve  of  the  dorsal  mouth,  or  notostome,  is  broken.  Fig.  63.  Chelyosoma 
maclomanum  Brod.  &  Sow.,  Y3  natural  size,  from  Point  Barrow,  Alaska. 

Pterichthys,  is  a  well-known  form  of  the  Devonian  period.  This 
genus  retained  its  tail,  which  was  the  cause,  in  connection  with 
the  i^resence  of  lateral  fin-like  appendages,  of  its  having  been  sup- 
posed to  be  a  fish,  by  Agassiz,  Hugh  Miller,  and  others.  It  is  pos- 
sible that  the  American  Bothriolepis  canadensis  lost  its  tail,  as  in 
the  majority  of  Urochorda.  The  tunicate  which  approaches  near- 
est to  the  Antiarcha  is  the  Arctic  Chelyosoma. 

From  the  Antiarcha  to  the  Acrania  and  Craniata,  then,  the 
line  is  an  ascending  one. 


*  March,  1885,  p.  289. 


324:        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 


lY.    THE   LIl^E   OF   THE    PISCES. 

The  fishes  form  various  series  and  subseries,  and  the  tracing 
of  all  of  them  is  not  yet  practicable,  owing  to  the  deficiency  in 
our  knowledge  of  the  earliest  or  ancestral  forms.  Thus  the  ori- 
gins of  the  four  subclasses,  Holocephali,  Dipnoi,  Elasmobranchii, 
and  Teleostomi,  are  lost  in  the  obscurity  of  the  early  Palaeozoic 
ages. 

A  comparison  of  the  four  subclasses  just  named  shows  that 
they  are  related  in  pairs.  The  Holocephali  and  Dipnoi  haye  no 
distinct  suspensory  segment  for  the  lower  jaw,  while  the  Elasmo- 
branchii and  Hyopomata  have  such  a  separate  element.  The  lat- 
ter, therefore,  present  one  step  in  the  direction  of  complication  be- 
yond the  former  ;  but  whether  the  one  type  is  descended  from  the 
other,  or  whether  both  came  from  a  common  ancestor  or  not,  is 
unknown.  If  one  type  be  derived  from  the  other,  it  is  not  certain 
which  is  ancestor,  and  whether  the  process  has  been  one  of  advance 
or  retrogression.  The  fauna  of  the  Permian  epoch  throws  some 
light  on  the  relations  of  these  subclasses  in  other  respects.  The 
order  of  the  Ichthyotomi,*  while  belonging  technically  to  the 
Elasmobranchi,  presents  characters  of  both  the  Dipnoi  and  the 
Teleostomi.  It  is  so  near  to  the  Dipnoi  in  the  characters  of  the 
skull  that  nothing  save  the  presence  of  a  free  suspensor  of  the 
lower  jaw  prevents  its  entering  that  subclass.  It  indicates  that 
the  one  of  these  divisions  is  descended  from  the  other,  or  both 
from  a  common  division  which  may  well  be  the  group  Ichthyotomi 
itself.  In  case  the  Elasmobranchi  have  descended  from  the  Ich- 
thyotomi, they  have  undergone  degeneracy,  as  the  Ichthyotomi 
have  a  higher  degree  of  ossification  and  differentiation  of  the  bones 
of  the  skull.  If  they  descended  from  a  purely  cartilaginous  type 
of  Dipnoi,  they  have  advanced,  in  the  addition  of  the  free  hyo- 
mandibular.  If  the  Dipnoi  have  descended  from  either  division, 
they  have  retrograded,  in  the  loss  of  the  free  hyomandibular.  As 
regards  the  Teleostomi,  we  have  a  clear  advance  over  the  other 
subclasses  in  the  presence  of  the  maxillary  arch  and  the  opercular 
apparatus. 

Too  little  is  known  of  the  history  of  the  subclasses,  excepting 
the  Teleostomi,  for  us  to  be  able  to  say  much  of  the  direction  of 

*  See  "  Palseontological  Bulletin,"  No.  38,  E.  D.  Cope,  18S4,  p.  512,  on  the  genus 
Didvmodus. 


EVOLUTION  OF  THE   VERTEBRATA.  325 

the  descent  of  their  contained  orders.  On  the  sharks  some  light 
is  shed  by  the  discovery  of  tlie  genus  Chlamydoselachus  Garman,* 
which  is  apparently  nearly  related  to  the  Cladodonts  of  the  Devo- 
nian seas.  This  genus  has  more  numerous  branchial  slits  than  all 
but  two  of  the  genera  of  existing  sharks,  and  it  differs  from  all  but 
these  two  in  having  a  more  perfect  articulation  between  the  tooth- 
bearing  bones  and  the  cranium.  Of  the  Teleostomi  a  much  clearer 
history  is  accessible.  It  has  three  primary  divisions  or  tribes  which 
differ  solely  in  the  structure  of  the  supports  of  the  fins.  In  the 
first  division,  the  Crossopterygia,  the  anterior  limbs  have  numerous 
basilar  bones  which  are  supported  on  a  peduncle  of  axial  bones. 
The  posterior  limbs  are  similar.  In  the  second  division,  or  Chron- 
drostei  (the  sturgeons,  etc. ),  the  posterior  limb  remains  the  same, 
while  the  anterior  limbs  have  undergone  a  great  abbreviation  in 
the  loss  of  the  axial  bones  and  the  reduction  of  the  number  and 
length  of  the  basilar  bones.  In  the  third  group,  or  Actinopteri,t 
both  limbs  have  undergone  reduction,  the  basilar  bones  in  the  pos- 
terior fin  being  almost  all  atrophied,  while  those  of  the  fore  limb 
are  much  reduced  in  number. 

The  phylogeny  of  these  tribes  is  not  easy  to  make  out  at  pres- 
ent. The  descent  has  been,  no  doubt,  in  the  order  named  in  time, 
but  the  starting-point  is  yet  uncertain.  Thus  the  Chondrostei 
appear  later  in  time  than  either  of  the  other  tribes,  a  history 
which  probably  only  represents  our  ignorance.  The  characters  of 
the  genus  Crossopholis  Cope,  from  the  American  Eocene,  strongly 
suggest  that  the  existing  forms  have  descended  from  scaled  an- 
cestors. The  Crossopterygian  fore  limb,  with  its  arm-like  axis, 
tells  of  the  origin  of  the  first  limbed  vertebrates,  the  Batrachia, 
whose  skull-structure,  however,  only  permits  their  derivation 
from  the  Dipnoi  or  Ilolocephali.  As  the  former  subclass  has  the 
Crossopterygian  fin-structure,  we  can  safely  regard  them  as  the 
ancestors  of  the  Batrachia,  while  the  Crossopterygia  are  a  side- 
line from  a  similar  type,  probably  the  Ichthyotomi,  because  these 
have  a  free  suspensor  of  the  lower  jaw.  But  of  the  structure  of 
the  fins  of  the  Ichthyotomi  unfortunately  we  know  nothing.  If 
this  position  be  true,  then  the  successive  derivation  of  the  Chon- 
drostei and  the  Teleostomi  in  one  line  is  rendered  probable.  The 
modification  of  structure  has  consisted  in  the  contraction  of  the 


*  "Proceedings  American  Assoc.  Adv.  Sci.,"  1884. 

f  Partly  agrees  with  the  Teleostei  of  Miiller,  but  includes  many  of  his  Ganoidea. 


326        THE   STRUCTUKAL  EVIDENCE   OF  EYOLUTION. 

supporting  elements  of  the  pectoral  and  ventral  fins  by  the  reduc- 
tion of  their  numbers  and  length.  According  to  paleontological 
history,  however,  the  tribe  of  Teleostomi  with  most  contracted 
fins,  Actinopteri,  appeared  in  the  Coal  Measures  (Paleoniscidse), 
or  very  soon  after  the  Crossopterygia  in  the  Devonian. 

The  descent  of  the  fishes  in  general  has  witnessed,  then,  a 
contraction  of  the  limbs  to  a  very  small  compass,  and  their  sub- 
stitution by  a  system  of  accessory  radii.  This  has  been  an  ever- 
widening  divergence  from  the  type  of  the  higher  Vertebrata,  and 
from  this  standpoint,  and  also  a  view  of  the  ^Hoss  of  parts  with- 
out complementary  addition  of  other  parts,"  may  be  regarded  as 
a  process  of  degradation. 

Taking  up  the  great  division  of  the  Actinopteri,  which  em- 
braces most  of  the  species  of  living  fishes,  we  can  trace  the  direc- 
tion of  descent  largely  by  reference  to  their  systematic  relations 
when  we  have  no  fossils  to  guide  us. 

The  three  sub  tribes  adopted  by  Jordan  represent  three  series 
of  the  true  fishes  which  indicate  lines  of  descent.  The  Holostei 
include  the  remainder  of  the  old  ganoids  after  the  subtraction  of 
the  Crossopterygia  and  the  Chondrostei.  They  resemble  these 
forms  in  the  muscular  bulbus  arteriosus  of  the  heart  and  in  the 
chiasm  of  the  optic  nerves.  Both  of  these  characters  are  com- 
plexities which  the  two  other  divisions  do  not  possess,  and  which, 
as  descendants  coming  later  in  time,  must  be  regarded  as  inferior, 
and  therefore  to  that  extent  degenerate.  Of  these  divisions  the 
Physostomi  approach  nearest  the  Holostei,  and  are  indeed  not 
distinctly  definable  without  exceptions.  The  third  division,  or 
Physoclysti,  shows  a  marked  advance  beyond  the  others  in  :  (1) 
the  obliteration  of  the  primitive  trachea,  or  ductus  pneumaticus, 
which  connects  the  swim-bladder  and  oesophagus  ;  (2)  the  advance 
of  the  ventral  fins  from  the  abdomen  forward  to  the  throat ;  (3) 
the  separation  of  the  parietal  bones  by  the  supraoccipital ;  (4) 
the  presence  of  numerous  spinous  rays  in  the  fins ;  and  (5)  the 
roughening  of  the  edges  of  the  scales,  forming  the  ctenoid  type. 
There  are  more  or  less  numerous  exceptions  to  all  of  these  char- 
acters. The  changes  are  all  further  divergencies  from  the  other 
vertebrate  classes,  or  away  from  the  general  line  of  ascent  of  the 
vertebrate  series  taken  as  a  whole.  The  end  gained  is  specializa- 
tion ;  but  whether  the  series  can  be  called  either  distinctively  pro- 
gressive or  retrogressive,  is  not  so  clear.  The  development  of 
osseous  spines,  rough  scales,  and  other  weai)ons  of  defense,  together 


EVOLUTION"  OF  THE  YERTEBRATA.  327 

with  the  generally  superior  energy  and  tone  which  prevail  among 
the  Physoclysti,  characterize  them  as  superior  to  the  Physostomi, 
but  their  departure  from  the  ascending  line  of  the  Vertebrata  has 
another  appearance. 

The  descent  of  the  Physoclystous  fishes  has  probably  been 
from  Ilolostean  ancestors,  both  with  and  without  the  intervention 
of  Physostomous  forms.  This  is  indicated  by  increase  in  the 
number  of  basilar  bones  in  the  fins  of  families  which  have  pec- 
toral ventral  fins,  as  in  the  extinct  genus  Dorypterus.* 

The  Physostomi  display  three  or  four  distinct  lines  of  descent. 
The  simplest  type  is  represented  by  the  order  Isospondyli,  and 
paleontology  indicates  clearly  that  this  order  is  also  the  oldest, 
as  it  dates  from  the  Trias  at  least.  In  one  line  the  anterior  dor- 
sal vertebrae  have  become  comjolicated,  and  form  an  interlocking 
mass  which  is  intimately  connected  with  the  sense  of  hearing. 
This  series  commences  with  the  Characinidae,  passes  through  the 
Cyprinidae,  and  ends  with  the  Siluridae.  The  arrangements  for 
audition  constitute  a  superadded  complication,  and  to  these  are 
added  in  the  Siluroids  defensive  spines  and  armor.  Some  of 
this  order,  however,  are  distinctly  degenerate,  as  the  soft  pur- 
blind Ageniosus,  and  the  parasitic  Stegophilus  and  Vandellia, 
which  are  nearly  blind,  without  weapons,  and  with  greatly  re- 
duced fins. 

The  next  line  (the  Haplomi,  pike,  etc.)  loses  the  precoracoid 
arch  and  has  the  parietal  bones  separated,  both  characters  of  the 
Physoclysti.  This  group  was  apparently  abundant  during  the 
Cretaceous  period,  and  it  may  have  given  origin  to  many  of  the 
Physoclysti. 

Another  line  also  loses  the  precoracoid,  but  in  other  respects 
diverges  totally  from  the  Physoclysti  and  all  other  Physostomi. 
This  is  the  line  of  the  eels.  They  next  lose  the  connection  be- 
tween the  scapular  arch  and  the  skull,  which  is  followed  by  the 
loss  of  the  pectoral  fin.  The  ventral  fin  disappeared  sooner.  The 
palatine  bones  and  teeth  disappear,  and  the  suspensor  of  the  lower 
jaw  grows  longer  and  loses  its  symplectic  element.  The  opercu- 
lar bones  grow  smaller,  and  some  of  them  disappear.  The  ossi- 
fication of  most  of  the  hyoid  elements  disappears,  and  some  of 
their  cartilaginous  bases  even  vanish.  These  forms  are  the  marine 
eels  or  Colocephali.     The  most  extraordinary  example  of  speciali- 

*  See  "  Proceeds.  Amer.  Assoc.  Adv.  Science,"  1 SVS,  p.  297. 


328        THE   STRUCTURAL  EVIDENCE  OF  EVOLUTION'. 

zation  and  degeneracy  is  seen  in  the  abyssal  eels  of  the  family 
Eurypharyngidge.  Here  all  the  degenerate  features  above  men- 
tioned are  present  in  excess,  and  others  are  added,  as  the  loss  of 
ossification  of  a  part  of  the  skull,  almost  total  obliteration  of  the 
hyoid  and  scapular  arches,  and  the  semi-Dotochordal  condition  of 
the  vertebral  column,  etc. 

The  Physoclysti  nearest  the  Physostomi  have  abdominal  ven- 
tral fins,  and  belong  to  several  orders.  It  is  such  types  as  these 
that  may  be  supposed  to  have  been  derived  directly  from  Holos- 
tean  ancestors.  They  appear  in  the  Cretaceous  period  (Derceti- 
dae),  along  with  the  types  that  connect  with  the  Physostomi 
(Haplomi).  Intermediate  forms  between  these  and  typical  Phy- 
soclysti occur  in  the  Eocene  (Trichophanes,  Erismatopterus), 
showing  several  lines  of  descent.  The  Dercetidse  belong  appar- 
ently to  the  order  Hemibranchi,  while  the  Eocene  genera  named 
belong  apparently  to  the  Aphododiridse,  the  immediate  ancestor 
of  the  highest  Physoclysti,  the  Percomorphi.  The  order  Hemi- 
branchi is  a  series  of  much  interest.  Its  members  lose  the  mem- 
brane of  their  dorsal  spinous  fin  (Gasterosteidse),  and  then  the  fin 
itself  (Fistularia,  Pegasus).  The  branchial  apparatus  has  under- 
gone, as  in  the  eels,  successive  deossification  (by  retardation),  and 
this  in  direct  relation  to  the  degree  with  which  the  body  comes 
to  be  protected  by  bony  shields,  reaching  the  greatest  defect  in 
the  Amphisilidas.  One  more  downward  step  is  seen  in  the  next 
succeeding  order  of  the  Lophobranchii.  The  branchial  hyoid 
ap23aratus  is  reduced  to  a  few  cartilaginous  pieces,  and  the  bran- 
chial fringes  are  much  reduced  in  size.  In  the  Hippocampidae 
the  caudal  fin  disappears  and  the  tail  becomes  a  prehensile  organ 
by  the  aid  of  which  the  species  lead  a  sedentary  life.  The  mouth 
is  much  contracted  and  becomes  the  anterior  orifice  of  a  suctorial 
tube.  This  is  a  second  line  of  unmistakable  degeneracy  among 
true  fishes. 

The  Physoclysti  with  pectoral  ventral  fins  present  us  with  per- 
haps ten  important  ordinal  or  subordinal  divisions.  Until  the 
paleontology  of  this  series  is  better  known,  we  shall  have  diffi- 
culty in  constructing  phylogenies.  Some  of  the  lines  may,  how- 
ever, be  made  out.  The  accompanying  diagram  will  assist  in  un- 
derstanding them. 

The  Anacanthini  present  a  general  weakening  of  the  organiza- 
tion in  the  less  firmness  of  the  osseous  tissue  and  the  frequent 
reduction  in  the  size  and  character  of  the  fins.     The  caudal  ver- 


EVOLUTION   OF  THE   VERTEBRATA.  329 

tebrae  are  of  the  protocercal  type.  As  tliis  group  does  not  appear 
early  in  geological  time,  and  as  it  is  largely  represented  now  in 
the  abyssal  ocean  fauna,  there  is  every  reason  to  regard  it  as  a 
degenerate  type.*  The 
scyphobranch  line  presents 
a  specialization  of  the  su- 
perior pharyngeal  bones, 
which  is  continued  by  the 
Haplodoci  (Batrachid^e). 
This  can  not  be  called  a 
degenerate  line,  although 
the  fin-ravs  are  soft.  The 
Heterosomata  (flounders) 
found  it  convenient  to  lie 
on  one  side,  a  habit  which 
would  appear  to  result 
from  a  want  of  motive  en- 
ergy. The  fins  are  very 
inefficient  organs  of  move- 
ment in  them,  and  they 
are  certainly  no  rivals  for 
swift-swimming  fishes  in 
the  struggle  for  existence, 
excepting  as  they  conceal 
themselves.      In    order  to 

see   the   better  while   un-  S        'S      §       \^    13     "S 

seen,  the  inferior  eve  has  -^         S      ^       '^      c     .2 

turned  inward,    i.  e.,  up-  |        J     ^     A' I     2     ^ 

ward,  and  finally  has  pen-  ''^  "~^ 

etrated  to  the  superior 
surface,  so  that  both  eyes 
are  on  one  side.  This  pe- 
culiarity would  be  incred- 
ible if  we  did  not  know 
of  its  existence,  and  is  an 
illustration  of   the  extraordinary  powers  of  accommodation  pos- 

*  The  general  characters  of  the  deep-sea  fish-fauna  are  those  of  degeneracy. 
(Ed.  1886.) 

f  This  order  was  proposed  by  Gill  for  the  Eurypharyngidae,  and  is  now  added, 
(Ed.  1886.) 


330        THE  STRUCTURAL  EVIDENCE   OF  EVOLUTION". 

sessed  by  nature.  ThQ  Heterosomata  can  only  be  considered  a 
degenerate  group. 

The  double  bony  floor  of  the  skull  of  the  Distegous  percomorph 
fishes  is  a  complication  which  places  them  at  the  summit  of  the 
line  of  true  fishes.  At  the  summit  of  this  division  must  be  placed 
the  Pharyngognathi,  which  fill  an  important  role  in  the  economy 
of  the  tropical  seas,  and  the  fresh  waters  of  the  Southern  hemi- 
sphere. By  means  of  their  powerful  grinding  pharyngeal  appara- 
tus they  can  reduce  yege table  and  animal  food  inaccessible  to  other 
fishes.  The  result  is  seen  in  their  multifarious  species  and  innu- 
merable individuals  decked  in  gorgeous  colors,  and  often  reaching 
considerable  size.  This  is  the  royal  order  of  fishes,  and  there  is  no 
reason  why  they  should  not  continue  to  increase  in  importance  in 
the  present  fauna. 

Very  different  is  the  line  of  the  Plectognathi.  The  probable 
ancestors  of  this  division,  the  Epilasmia  (ChaetodontidaB,  etc.),  are 
also  abundant  in  the  tropical  seas,  and  are  among  the  most  brill- 
iantly colored  of  fishes.  One  of  their  peculiarities  is  seen  in  a 
shortening  of  the  brain-case  and  prolongation  of  the  jaws  down- 
ward and  forward.  The  utility  of  this  arrangement  is  probably  to 
enable  them  to  procure  their  food  from  the  holes  and  cavities  of 
the  coral  reefs  among  which  they  dwell.  In  some  of  the  genera 
the  muzzle  has  become  tubular  (Chelmo),  and  is  actually  used  as 
a  blow-gun  by  which  insects  are  secured  by  shooting  them  with 
drops  of  water.  This  shortening  of  the  basicranial  axis  has  pro- 
duced a  corresponding  abbreviation  of  the  hyoid  apparatus.  The 
superior  piharyngeal  bones  are  so  crowded  as  to  have  become  a 
series  of  vertical  plates  like  the  leaves  of  a  book.  These  charac- 
ters are  further  developed  in  the  Plectognathi.  The  brain-case  is 
very  small,  the  face  is  very  elongate,  and  the  mouth  is  much  con- 
tracted. The  bones  surrounding  it  in  each  jaw  are  co-ossified. 
The  axial  elements  (femora)  of  the  posterior  fins  unite  together, 
become  very  elongate,  and  lose  the  natatory  portion.  In  one  group 
(Orthagoriscidae)  the  posterior  part  of  the  vertebral  column  is  lost 
and  the  caudal  fin  is  a  nearly  useless  rudiment.  In  the  Ostracion- 
tidae  (which  may  have  had  a  different  origin,  as  the  pharyngeal 
bones  are  not  contracted)  the  natatory  powers  are  much  reduced, 
and  the  body  is  inclosed  in  an  osseous  carapace  so  as  to  be  capable 
of  very  little  movement.  The  entire  order  is  deficient  in  osseous 
tissue,  the  bones  being  thin  and  weak.  It  is  a  marked  case  of 
degeneracy. 


EVOLUTION  OF  THE  VERTEBRATA.  331 

There  are  several  evident  instances  of  sporadic  degeneracy  in 
other  orders.  One  of  these  is  the  case  of  the  family  of  the  Icos- 
teidse,  fishes  from  deep  waters  off  the  coast  of  California.  Al- 
though members  of  the  Percomorphi,  the  skeleton  in  the  two  gen- 
era Icosteus  and  Icichthys  is  unossified,  and  is  perfectly  flexible. 
Approximations  to  this  state  of  things  are  seen  in  the  parasitic 
genus  Cyclopterus,  and  in  the  ribbon-fishes,  Trachypteridee. 

Thus  nearly  all  the  main  lines  of  the  Physoclysti  are  degener- 
ate ;  the  exceptions  are  those  that  terminate  in  the  Scombridse 
(mackerel),  Serranidae,  and  Scaridae  (Pharyngognathi). 

Y.    THE    LIKE   OF  THE   BATRACHIA. 

We  know  Batrachia  first  in  the  Coal  Measures.  They  reach  a 
great  development  in  the  Permian  epoch,  and  are  represented  by 
large  species  in  the  Triassic  period.  From  that  time  they  dimin- 
ish in  numbers,  and  at  the  present  day  form  an  insignificant  part 
of  the  vertebrate  fauna  of  the  earth.  The  history  of  their  suc- 
cession is  told  by  a  table  of  classification  such  as  I  give  below  : 

I.  Supraoccipital,  intercalary  and   supratemporal  bones   present.      Propodial 

bones  distinct. 

Vertebral  centra,  including  atlas,  segmented,  one  set  of  segments  together  support- 
ing one  arch Rhachitomi. 

Vertebrae  segmented,  the  superior  and  inferior  segments  each  complete,  forming  two 
centra  to  each  arch EmbolomeH. 

Vertebral  centra,  including  atlas,  not  segmented,  one  to  each  arch StegoccpJiali. 

II.  Supraoccipital  and  supratemporal  bones  wanting.     Frontal  and  propodial 

bones  distinct. 

a.  An  OS  intercalare, 

A  palatine  arch  and  separate  caudal  vertebrae Proteida. 

aa.  No  OS  intercalare. 
A  maxillary  arch ;  palatine  arch  imperfect ;  nasals,  premaxillaries  and  caudal  verte- 
brae distinct Urodela* 

No  maxillary  or  palatine  arches ;  nasals  and  premaxillary,  also  caudal  vertebrae,  dis- 
tinct  Trachystomata, 

III.  Supraoccipital,  intercalare  and  supratemporal  bones  wanting.      Frontals 
and  parietals  connate ;  propodial  bones  and  caudal  vertebrae  confluent. 

Premaxillaries  distinct  from  nasals ;  no  palatine  arch  ;  astragalus  and  calcaneum 
elongate,  forming  a  distinct  segment  of  the  limb Anura. 

The  probable  phylogeny  of  these  orders  as  imperfectly  indi- 
cated by  paleontology  is  as  follows  : 


* 


Probably  includes  the  Gymnophiona. 


332        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION". 

Anura 

Urodela  Trachjstomata  * 

I 
Proteida 

Stegocephali 

I. 
Embolomeri  Rhachitomif 

Ganocephala  J 

An  examination  of  the  above  tables  shows  that  there  has  been 
in  the  history  of  the  Batrachian  class  a  reduction  in  the  number 
of  the  elements  composing  the  skull,  both  by  loss  and  by  fusion 
with  each  other.  It  also  shows  that  the  vertebrae  have  passed  from 
a  notochordal  state  with  segmented  centra,  to  biconcave  centra, 
and  finally  to  ball-and-socket  centra,  with  a  great  reduction  of  the 
caudal*  series.  It  is  also  the  fact  that  the  earlier  forms  (those  of 
the  Permian  epoch)  show  the  most  Mammalian  characters  of  the 
tarsus  and  of  the  pelvis.  The  latter  forms,  the  salamanders, 
show  a  more  generalized  form  of  carpus  and  tarsus  and  of  pelvis 
also.  In  the  latest  forms,  the  Anura,  the  carpus  and  tarsus  are 
reduced  through  loss  of  parts,  except  that  the  astragalus  and  cal- 
caneum  are  phenomenally  elongate.  We  have  then,  in  the  Batra- 
chian series,  a  somewhat  mixed  kind  of  change  ;  but  it  princijDally 
consists  of  concentration  and  consolidation  of  parts.  The  ques- 
tion as  to  whether  this  process  is  one  of  progression  or  retrogres- 
sion may  be  answered  as  follows  :  If  degeneracy  consists  in  **the 
loss  of  parts  without  complementary  addition  of  other  parts,"  then 
the  Batrachian  line  is  a  degenerate  line.  This  is  only  partly  true 
of  the  vertebral  column,  which  presents  the  most  primitive  char- 
acters in  the  early,  Permian,  genera  (Rhachitomi).  If  departure 
from  the  nearest  approximation  to  the  Mammalia  is  degeneracy, 
then  the  changes  in  this  class  come  under  that  head.  The  carpus, 
tarsus,  and  scapular  and  pelvic  arches  of  the  Rachitomi  are  more 
Mammalian  than  are  those  of  any  of  their  successors.  || 

*  The  Trachystomata  probably  came  from  the  Urodela  by  a  process  of  degener- 
acy.    See  "American  Naturalist,"  Dec,  1 885.     (Ed.  1886.) 

f  Includes  the  Eryopidae. 

X  Includes  Trimcrorhachidae  and  Archegosauridae ;  and  is  distinguished  from  the 
Rhachitomi  only  by  the  presence  of  a  single  and  cotyloid  articulation  of  the  skull 
with  the  atlas. 

*  This  reduction  extends  to  the  dorsal  series  as  well.     (Ed.  1S8G.) 

11  This  should  read,  than  their  latest,  or  anurous  successors.     (Ed.  1886.) 


EVOLUTIOI!^   OF   THE  VERTEBRATA.  333 

There  are  several  groups  which  show  special  marks  of  degen- 
eracy. Such  are  the  reduced  maxillary  bones  and  persistent  gills 
of  the  Proteida;  the  absence  of  the  maxillary  bones  and  the 
presence  of  gills  in  the  Trachystomata  ;  the  loss  of  a  pair  of  legs 
and  feebleness  of  the  remaining  pair  in  the  sirens ;  and  the  ex- 
treme reduction  of  the  limbs  in  Amphiuma.  Such  I  must  also 
regard,  with  Lankester,  the  persistent  branchiae  of  the  Siredons. 
I  may  add  that  in  the  brain  of  the  Proteid  Necturus  the  hemi- 
spheres are  relatively  larger  than  in  the  Anura,  which  are  at  the 
end  of  the  line. 

It  must  be  concluded,  then,  that  in  many  respects  the  Ba- 
trachia  have  undergone  degeneracy  with  the  passage  of  time. 

VI.    THE   KEPTILIAl:^   LIKE. 

As  in  the  case  of  the  Batrachia,  the  easiest  way  of  obtaining  a 
general  view  of  the  history  of  this  class  is  by  throwing  their  prin- 
cipal structural  characters  into  a  tabular  form.  As  in  the  case  of 
that  class,  I  commence  with  the  oldest  forms  and  end  with  the 
latest  in  the  order  of  time,  which,  as  usual,  corresponds  with 
the  order  of  structure.  I  except  from  this  the  first  order,  the 
Ichthyopterygia,  which  we  do  not  know  prior  to  the  Triassic 
period  :  * 

A.  Extremities  not  differentiated  in  form  beyond  proximal  segment. 

I.  Os  quadratum  immovably  articulated  to  squamosal,  etc. 

Tubercular  and  capitular  rib-articulations  present  and  distinct. .  .1.  Ichthyopterygia. 
AA.  Elements  of  extremities  differentiated. 

II.  Os  quadratum  immovably  articulated ;  capitular  and  tubercular  rib-articula- 

tions distinct.     Archosauria. 
Pubis  and  ischium  united,  and  with  little  or  no  obturator  foramen ;  one  posterior 

cranial  arch  ;  limbs  ambulatory ;  a  procoracoid 2.   Theromorpha. 

Ischium  and  pubis  distinct,  the  latter  directed  forward,  backward,  or  downward ; 
two  postei'ior  cranial  arches;  limbs  ambulatory;  no  procoracoid 

3.  Dinosawia.j- 
Ischium  and  pubis  united  ;  two  postcranial  arches  ;  anterior  limbs  volant 

4.   Ornlthosauria. 

III.  Os  quadratum  closely  united  to  cranial  arches ;    but  one  rib-articulation. 
Synaptosauria. 

*  Generally  similar  to  the  system  published  by  me  in  "  Proceedings  Amer.  Ass. 
Adv.  Science,"  xix,  p.  233. 

f  This  definition  includes  the  Crocodilia  in  the  Dinosauria,  as  it  is  absolutely 
connected  with  the  typical  Dinosaurs  by  the  Opisthocoela  (Sauropoda  Marsh). 


334        THE   STPwUCTURAL  EVIDENCE  OF  EVOLUTION. 

Distinct  hyposternal  and  postabdominal  bones ;  ribs  joining  each  two  vertebrae,  and 
generally  forming  a  carapace  ;  one  posterior  cranial  arch 5.   Testudinata. 

Hyposternal  and  postabdominal  bones  not  distinct ;   two  posterior  cranial  arches ; 
ribs  attached  to  one  vertebra ;  a  sternum ;  ?  no  procoracoid 

6.  RhyncliocepJialia. 

Hyposternal  and  postabdominal  bones  not  distinct ;  two  posterior  cranial  arches ; 
ribs  attached  to  one  centrum ;  no  sternum ;  *  a  procoracoid . .  Y.  Sauropterygia. 

IV.  Os  quadratum  attached  only  at  the  proximal  extremity,  and  more  or  less 
movable;  ribs  with  one  head.     Streptostylica.f 
Brain-case  membranous  in  front  of  prootic  bone ;  trabecula  not  persistent 

8.  Lacertilia. 
Brain-case  with  osseous  walls  anterior  to  prootic ;  a  scapular  arch  and  sternum 

9.  PythonomorpJia. 

Brain-case  with  osseous  walls  anterior  to  prootic ;  no  scapular  arch  nor  sternum ; 

trabecular  grooves  of  sphenoid  and  presphenoid  bones 10.   Ophidia. 

An  inspection  of  the  characters  of  these  ten  orders,  and  their 
consideration  in  connection  with  their  geological  history,  will  give 
a  definite  idea  as  to  the  character  of  their  evolution.  The  history 
of  the  class,  and  therefore  the  discussion  of  the  question,  is  limited 
in  time  to  the  period  which  has  elapsed  since  the  Permian  epoch 
inclusive,  for  it  is  then  that  the  Eeptilia  enter  the  field  of  our 
knowledge.  During  this  period  but  one  order  of  reptiles  in- 
habited the  earth,  so  far  as  now  known,  that  of  the  Theromorpha. 
The  important  character  and  role  of  this  type  may  be  inferred 
from  the  fact  that  they  are  structurally  nearer  to  both  the  Ba- 
trachia  and  the  Mammalia  than  any  other,  but  present  characters 
which  render  it  probable  that  all  the  other  reptiles,  with  possibly 
the  exception  of  the  Ichthyopterygia,  derived  their  being  from 
them.     The  phylogeny  may  be  thus  expressed  : 


Dinosauria      Testudinata      Ehynchocephalia       Lacertilia      Ophidia 

~    \      / 

Pythonomorpha  J 


(Crocodilia) 
Pterosauria 

DinosauriaX  Sauropterygia^ 

/ 
/ 
/ 

Ichthyopterygia  Theromorpha 

*  Episternum  present. 

f  It  is  quite  possible  that  the  three  divisions  of  this  head  form  one  natural 
order,  the  Streptostylica,  or  Squamata. 

X  Some  unknown  type  of  this  order  will  represent  the  ancestor  of  the  Ophidia, 
while  the  Lacertilia  may  have  come  directly  from  the  Theromorpha.     (Ed.  1886.) 


EVOLUTION   OF  THE   VERTEBRATA.  335 

In  the  first  jDlace,  this  line  departs  with  lapse  of  time  from  the 
primitive  and  ancestral  order,  the  Theromorpha,  in  two  respects  : 
First,  in  the  loss  of  the  capitular  articulation  of  the  ribs,  and,  sec- 
ond, in  the  gradual  elongation  and  final  freedom  of  the  suspensory 
bone  of  the  lower  jaw  (the  os  quadratum).  In  so  departing  from 
the  Theromorpha,  it  also  departs  from  the  mammalian  type.  The 
ribs  assume  the  less  perfect  kind  of  attachment  which  the  mam- 
mals only  exhibit  in  some  of  the  whales,  and  the  articulation  of 
the  lower  jaw  loses  in  strength,  while  it  gains  in  extensibility,  as 
is  seen  in  the  development  of  the  line  of  the  eels  among  fishes. 
The  end  of  this  series,  the  snakes,  must  therefore  be  said  to  be 
the  result  of  a  process  of  creation  by  degeneration,  and  their  lack 
of  scapular  arch  and  fore  limb  and  usual  lack  of  pelvic  arch  and 
hind  limb,  are  confirmatory  evidence  of  the  truth  of  this  view  of 
the  case. 

Secondly,  as  regards  the  ossification  of  the  anterior  part  of  the 
brain-case.  This  is  deficient  in  some  of  the  Theromorpha,  the  an- 
cestral order,  which  resemble  in  this,  as  in  many  other  things, 
the  contemporary  Batrachia.  Some  of  them,  however  (Diadecti- 
dae),  have  the  brain  comjDletely  inclosed  in  front.  The  late  orders 
mostly  have  the  anterior  walls  membranous,  but,  in  the  strepto- 
stylicate  series  at  the  end,  the  skull  in  the  snakes  becomes  en- 
tirely closed  in  front.  In  this  respect,  then^  the  latter  may  be 
said  to  be  the  highest  or  most  perfect  order. 

As  regards  the  scapular  arch,  including  the  sternum,  no  order 
l^ossesses  as  many  elements  as  thoroughly  articulated  for  the  use 
of  the  anterior  leg  as  the  Permian  Theromorpha,  though  the  cor- 
acoid  is  of  reduced  size.  In  all  the  orders  there  is  loss  of  parts, 
excepting  only  in  the  Ornithosauria  and  the  Lacertilia.  In  the 
former  the  adaptation  is  to  flying.  The  latter  retain  nearly  the 
Theromorph  type,  enlarging  the  coracoid.  An  especial  side  de- 
velopment is  the  modification  of  abdominal  bones  into  two  pecul- 
iar elements  to  be  united  with  the  scapular  arch  into  a  plastron, 
seen  in  the  Testudinata.  In  this  part  of  the  skeleton  the  orders 
are  generally  degenerate,  the  last  one,  the  Ophidia,  especially  so. 

The  pelvic  arch  has  a  more  simple  history.  Again,  in  the 
Theromorpha  we  have  the  nearest  approach  to  the  Mammalia. 
The  only  other  order  which  displays  similar  characters  is  the 
Ornithosauria  (Dimorphodon,  according  to  Seeley).  In  the  Dino- 
sauria  we  have  a  side  modification  which  is  an  adaptation  to  the 
erect  or  bipedal  mode  of  progression,  the  inferior  bones  being 


336        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

thrown  backward  so  as  to  support  the  viscera  in  a  more  posterior 
position.  This  is  an  obvious  necessity  to  a  bipedal  animal  where 
the  vertebral  column  is  not  perpendicular,  as  in  birds.  And  it 
is  from  the  Dinosauria  that  the  birds  are  supposed  to  have  arisen. 
(Plates  XV  and  XVI.)  The  main  line  of  the  Eeptilia,  however, 
departs  from  both  the  mammalian  and  the  avian  type  and  loses 
in  strength  as  compared  with  the  former.  In  the  latest  orders, 
the  Phythonomorpha  and  Ophidia,  the  pelvis  is  rudimental  or 
absent. 

As  regards  the  limbs,  the  degeneracy  is  well  marked.  No 
reptilian  order  of  later  ages  apj^roaches  so  near  to  the  Mammalia 
in  these  parts  as  do  the  Permian  Theromorpha.  This  approxi- 
mation is  seen  in  the  internal  epicondylar  foramen  and  well-devel- 
oped condyles  of  the  humerus,  and  in  the  well-differentiated 
seven  bones  of  the  tarsus.  The  epicondylar  foramen  is  only  re- 
tained in  later  reptiles  in  the  Ehynchocephalian  Hatteria  (Dollo)  ; 
and  the  condyles  of  the  Dinosauria  and  all  of  the  other  orders, 
excepting  the  Ornithosauria  and  some  Lacertilia,  are  greatly 
wanting  in  the  strong  characterization  seen  in  the  Theromorpha. 
The  posterior  foot  seems  to  have  stamped  out  the  greater  part  of 
the  tarsus  in  the  huge  Dinosauria,  and  it  is  reduced,  though  to  a 
less  degree,  in  all  the  other  orders.  In  the  paddled  Sauroptery- 
gia,  dwellers  in  the  sea,  the  tarsus  and  carpus  have  lost  all  char- 
acterization, probably  by  a  process  of  degeneracy,  as  in  the  mam- 
malian whales.  This  is  to  be  inferred  from  the  comparatively 
late  period  of  their  appearance  in  time.  The  still  more  unspecial- 
ized  feet  and  limbs  of  the  Ichthyosaurus  (Ichthyopterygia)  can 
not  yet  be  ascribed  to  degeneracy,  for  their  history  is  too  little 
known.  At  the  end  of  the  line,  the  snakes  present  us  with  another 
evidence  of  degeneracy.  But  few  have  a  pelvic  arch  (Stenostomi- 
dse  Peters),  while  very  few  (Peropoda)  have  any  trace  of  a  poste- 
rior limb. 

The  vertebrae  are  not  introduced  into  the  definitions  of  the 
orders,  since  they  are  not  so  exclusively  distinctive  as  many  other 
parts  of  the  skeleton.  They  nevertheless  must  not  be  overlooked. 
As  in  the  Batrachia,  the  Permian  orders  show  inferioritv  in  the 
deficient  ossification  of  the  centrum.  Many  of  the  Theromorpha 
are  notochordal,  a  character  not  found  in  any  later  order  of 
reptiles  excepting  in  a  few  Lacertilia  (Gecconidaa).  They  thus 
differ  from  the  Mammalia,  whose  characters  are  approached  more 
nearly  by  some   of   the   terrestrial   Dinosauria   in   this   respect. 


EVOLUTION   OF   THE   VERTEBRATA.  337 

Leaving  this  order,  we  soon  reach  the  prevalent  ball-and-socket 
type  of  the  majority  of  Reptilia.  This  strong  kind  of  articula- 
tion is  a  need  which  accompanies  the  more  elongated  column 
which  itself  results  at  first  from  the  posterior  direction  of  the 
ilium.  In  the  order  with  the  longest  column,  the  Ophidia,  a  sec- 
ond articulation,  the  zygosphen,  is  introduced.  The  mechanical 
value  of  the  later  reptilian  vertebral  structure  is  obvious,  and  in 
this  respect  the  class  may  be  said  to  present  a  higher  or  more 
perfect  condition  than  the  Mammalia. 

In  review  it  may  be  said  of  the  reptilian  line,  that  it  exhibits 
marked  degeneracy  in  its  skeletal  structure  since  the  Permian 
epoch  ;  the  exception  to  this  statement  being  in  the  nature  of  the 
articulations  of  the  vertebrae.  And  this  specialization  is  an  adap- 
tation to  one  of  the  conditions  of  degeneracy,  viz.,  the  weakening 
and  final  loss  of  the  limbs  and  the  arches  to  which  they  are  at- 
tached. 

The  history  of  the  development  of  the  brain  in  the  Eeptilia 
presents  some  interesting  facts.  In  the  Diadectid  family  of  the 
Permian  Theromorpha  it  is  smaller  than  in  a  Boa  constrictor, 
but  larger  than  in  some  of  the  Jurassic  Dinosauria.  Marsh  has 
shown  that  some  of  the  latter  possess  brains  of  relatively  very 
narrow  hemispheres,  so  that  in  this  organ  those  gigantic  reptiles 
were  degenerate,  while  the  existing  streptostylicate  orders  have 
advanced  beyond  their  Permian  ancestors. 

There  are  many  remarkable  cases  of  what  may  now  be  safely 
called  degradation  to  be  seen  in  the  contents  of  the  orders  of 
reptiles.*  Among  tortoises  may  be  cited  the  loss  of  the  rib- 
heads  and  of  one  or  two  series  of  phalanges  in  the  especially 
terrestrial  family  of  the  Testudinidae.  The  cases  among  the 
Lacertilia  are  the  most  remarkable.  The  entire  families  of  the 
Pygopodidse,  the  Aniellidse,  the  Anelytropidae,  and  the  Dibamidae 
are  degraded  from  superior  forms.  In  the  Anguidae,  Teidae,  and 
Scincidae,  we  have  series  of  forms  whose  steps  are  measured  by 
the  loss  of  a  pair  of  limbs,  or  of  from  one  to  all  the  digits,  and 
even  to  all  the  limbs.  In  some  series  the  surangular  bone  is  lost. 
In  others  the  eye  diminishes  in  size,  loses  its  lids,  loses  the  folds 
of  the  epidermis  which  distinguishes  the  cornea,  and  finally  is  en- 
tirely obscured  by  the  closure  of  the  ophthalmic  orifice  in  the 


*  Such  forms  in  the  Lacertilia  have  been  regarded  as  degradational  by  Lan- 
!ou] 

22 


kester  and  Bouhmger, 


PLATE  XV. 


o 

P 


o 


c 

cS 
o 


o 
o 

•  r-H 

CS 
02 

o 


r— t 

o 


CS 

P 
CO 
o 


CO 


S 

o 


PLATE  XVI. 


Diclonius  mirabilis  skull,  one  seventh  natural  size,  from  below. 


340        THE   STRUCTURAL  EVIDEISrCE   OF  EVOLUTION. 

true  skin.  Among  the  snakes  a  similar  degradation  of  the  organs 
of  sight  has  taken  place  in  the  order  of  the  Scolecophidia,  which 
live  underground,  and  often  in  ants'  nests.  The  Tortricidae  and 
UropeltidsB  are  burro  wing-snakes  which  display  some  of  the  earlier 
stages  of  this  process.  One  genus  of  the  true  snakes  even  (accord- 
ing to  Giinther)  has  the  eyes  obscured  as  completely  as  those  of 
the  inferior  types  above  named  (genus  Typhlogeophis). 

YII.    THE   AVIAIiT   LINE. 

The  paleontology  of  the  birds  not  being  well  known,  our  con- 
clusions respecting  the  character  of  their  evolution  must  be  very 
incomplete.  A  few  lines  of  succession  are,  however,  quite  ob- 
vious, and  some  of  them  are  clearly  lines  of  progress,  and  others 
are  lines  of  retrogression.  The  first  bird  we  know  at  all  com- 
pletely, is  the  celebrated  Archeoj^teryx  of  the  Solenhofen  slates 
of  the  Jurassic  period.  In  its  elongate  series  of  caudal  vertebrae 
and  the  persistent  digits  of  the  anterior  limbs  we  have  a  clear  in- 
dication of  the  process  of  change  which  has  produced  the  true 
birds,  and  we  can  see  that  it  involves  a  specialization  of  a  very 
pronounced  sort.  The  later  forms  described  by  Seeley  and  Marsh 
from  the  Cretaceous  beds  of  England  and  North  America,  some 
of  which  have  biconcave  vertebrae,  and  all  probably,  the  American 
forms  certainly,  possessed  teeth.  This  latter  character  was  evi- 
dently speedily  lost,  and  others  more  characteristic  of  the  subclass 
became  the  field  of  developmental  change.  The  parts  which  sub- 
sequently attained  especial  development  are  the  wings  and  their 
appendages  ;  the  feet  and  their  envelopes,  and  the  vocal  organs. 
Taking  all  things  into  consideration,  the  greatest  sum  of  progress 
has  been  made  by  the  perching  birds,  whose  feet  have  become 
effective  organs  for  grasping,  whose  vocal  organs  are  most  perfect, 
and  whose  flight  is  generally  good,  and  often  very  good.  In 
these  birds  also  the  circulatory  system  is  most  modified,  in  the 
Ibss  of  one  of  the  carotid  arteries. 

The  power  of  flight,  the  especially  avian  character,  has  been 
developed  most  irregularly,  as  it  appears  in  all  the  orders  in 
especial  cases.  This  is  apparent  so  early  as  in  the  Cretaceous 
toothed  birds  already  mentioned.  According  to  Marsh  the  Hes- 
peornithidae  have  rudimental  wings,  while  these  organs  are  well 
developed  in  the  Ichthyornithidae.  They  are  well  developed 
among  natatorial  forms  in  the  albatrosses  and  frigate  pelicans, 
and  in  the  skuas,   gulls,   and  terns  ;   among  rasorial  types  the 


EVOLUTION   OF  THE  VERTEBRATA.  341 

sand-grouse,  and,  among  the  adjacent  forms,  the  pigeons.  Then 
among  the  lower  insessores,  the  humming-birds  exceed  all  birds 
in  their  powers  of  flight,  and  the  swifts  and  some  of  the  Capri- 
mulgidae  are  highly  developed  in  this  respect.  Among  the  higher 
or  true  song  birds,  the  swallows  form  a  notable  example.  With 
these  high  specializations  occur  some  remarkable  deficiencies. 
Such  are  the  reduction  of  the  feet  in  the  Caprimulgidae,  swifts, 
and  swallows,  and  the  foetal  character  of  the  bill  in  the  same 
families.  In  the  syndactyle  families,  represented  by  the  king- 
fishers, the  condition  of  the  feet  is  evidently  the  result  of  a  pro- 
cess of  degeneration. 

A  great  many  significant  points  may  be  observed  in  the 
developmental  history  of  the  epidermic  structures,  especially  in 
the  feathers.  The  scale  of  change  in  this  respect  is  in  general  a 
rising  one,  though  various  kinds  of  exceptions  and  variations 
occur.  In  the  development  of  the  rectrices  (tail-feathers)  there 
are  genera  of  the  wading  and  rasorial  types,  and  even  in  the  in- 
sessorial  series,  where  those  feathers  are  greatly  reduced  or  abso- 
lutely wanting.     These  are  cases  of  degeneracy. 

There  is  no  doubt  that  the  avian  series  is  in  general  an  as- 
cending one. 

VIII.    THE   MAMMALIAN"   LIXE. 

Discoveries  in  paleontology  have  so  far  invalidated  the  ac- 
cepted definitions  of  the  orders  of  this  class  that  it  is  difficult  to 
give  a  clearly  cut  analysis,  especially  from  the  skeleton  alone. 
The  following  scheme,  therefore,  while  it  expresses  the  natural 
groupings  and  affinities,  is  defective  in  that  some  of  the  defini- 
tions are  not  without  exceptions  : 

I.  A  large  coracoid  bone  articulating  with  the  sternum. 
Marsupial  bones ;  fibula  articulating  with  proximal  end  of  astragalus 

1.  Monotrcmata. 

II,  Coracoid  a  small  process  co-ossified  with  the  scapula. 

o.  Marsupial  bones ;  palate  with  perforations  (vagina  double ;  placenta  and 
corpus  callosum  rudimental  or  wanting;  cerebral  hemispheres  small 
and  generally  smooth). 

But  one  deciduous  molar  tooth 2.  Marsupialia. 

aa.  No  marsupial  bones;    palate  entire  (one  vagina;  placenta  and  corpus 
callosum  well  developed). 
j8.  Anterior  limb  reduced  to  more  or  less  inflexible  paddles,  posterior 
limbs  wanting  (Mutilata). 


342        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

No  elbow-joint ;   carpals  discoid,  and  with  the  digits  separated  by  cartilage ;  lower 

jaw  without  ascending  ramus 3.   Cetacea, 

An  elbow-joint ;  carpals  and  phalanges  m  ith  normal  articulations ;  lower  jaw  with 

ascending  ramus 4.  Sirenia. 

j8^.  Anterior  limbs  with  flexible  joints  and  distinct  digits ;  ungual  pha- 
langes not  compressed  and  acute  at  apex*  (Ungulata  f). 
y.  Tarsal  bones  in  linear  series ;  carpals  generally  in  linear  series. 

Limbs  ambulatory ;  teeth  with  enamel 5.   Taxeojxxla.X 

77.  Tarsal  series  alternating;  carpal  series  linear. 
Cuboid  bone  partly  supporting  navicular,  not  in  contact  with  astragalus .  6.  Prohoscidia. 

777.  Both  tarsal  and  carpal  series  more  or  less  alternating. 
Os  magnum  not  supporting  scaphoides  ;    cuboid    supporting  astragalus ;    superior 

molars  tritubercular 7.  Arahlijpoda. 

Os  magnum  supporting  scaphoides  ;  superior  molars  quadritubercular  * 

8.  Diplarthra,\ 
/3/3j3.  Anterior  limbs  with  flexible  joints.     Ungual  phalanges  compressed 
and  pointed-^  (Unguiculata). 
e.  Teeth  without  enamel;  no  incisors. 

Limbs  not  volant;  hemispheres  small,  smooth 9.  Edentata. 

66.  Teeth  with  enamel ;  incisors  present. 
No  postglenoid  process ;  mandibular  condyle  round ;  limbs  not  volant ;  hemispheres 

small,  smooth 10.  Rodentia. 

Limbs  volant ;  hemispheres  small,  smooth 11.   Chiroptera. 

*  Except  the  Ilapalidse.  f  Lamarck,  "Zoologie  Philosophique,"  1809. 

X  This  order  has  the  following  suborders,  whose  association  is  now  made  for  the 
first  time : 

Carpal  series  linear ;   no  intermedium ;  fibula  not  interlocking  with  astragalus ;  no 

anapophyses ;  incisors  rooted ;  hallux  not  opposable. Condylartha. 

Carpal  series  linear ;    an  intermedium ;  fibula  interlocking  with  astragalus ;  hallux 

not  opposable Hyracoidea. 

An  intermedium ;  fibula  not  interlocking ;  anapophyses ;  hallux  opposable ;  incisors 

growing  from  persistent  pulps Dauhentonoidea. 

An  intermedium  ;  fibula  not  interlocking  ;  anapophyses;  hallux  opposable ;  incisors 

rooted ;  carpus  generally  linear Qiiadt^mana. 

No  intermedium ;  *  nor  anapophyses  ;  carpal  rows  alternating ;  incisors  rooted 

A  nthropoidea.\ 
The  only  difference  between  the  Taxeopoda  and  the  Bunotheria  is  in  the  unguli- 
form  terminal  phalanges  of  the  former  as  compared  with  the  clawed  or  unguiculate 
form  in  the  latter.     The  marmosets  among  the  former  division  are,  however,  fur- 
nished with  typical  claws. 

Some  may  prefer  to  use  the  term  Primates  in  place  of  Taxeopoda,  and  such  may 
be  the  better  course. 

*  Except  Pantolestes. 

II  This  order  includes  the  suborders  Pcrissodactyla  and  Artiodactyla.     It  is  the 
Ungulata  of  some  authors. 
^  Except  Mesonyx. 

*  Except  in  Sijnia  and  Hylobates.       t  Includes  the  Anthropoid  apes  and  man. 


EYOLUTTON  OF   THE   YERTEBRATA. 


843 


A  postglenoid  process;  mandibular  condyle  transverse;  limbs  not  volant;  no 
scapholunar  bone;*  hemispheres  small,  smooth 12.  BuiiotheriaA 

A  postglenoid  process ;  limbs  not  volant,  with  a  scapholunar  bone ;  hemispheres 
larger,  convoluted 13.   Carnivora. 

Paleontology  has  cleared  up  the  phylogeny  of  most  of  these 
orders,  but  some  of  them  remain  as  yet  unexplained.  This  is  the 
case  with  the  Cetacea,  the  Sirenia,  and  the  Taxeopoda.  The 
last-named  order  and  the  Marsupialia  can  be  supposed  with  much 
probability  to  have  come  oS  from  the  Monotremata,  but  there  is 
as  yet  no  paleontological  evidence  to  sustain  the  hypothesis.  Xo 
progress  has  been  made  in  unraveling  the  phylogeny  of  the  Ceta- 
cea and  Sirenia.  The  facts  and  hypotheses  as  to  the  phylogeny 
of  the  Mammalia  may  be  representad  in  the  following  diagram  : 


Diplarthra  Hyracoidea  Insectivora  Rodentia  Chiroptera 


Proboscidea 
Amblypoda 


Anthropoidea 

I 
Qaadrumana 


Edentata 


Carnivora 


Sirenia 
Cetacea 


Tillodonta 
Ta3niodonta    [     Oreodonta 


Oondylartbra 
Marsupialia  pt.J. 
Monotremata 


Marsupialia  pt. 


It  will  be  readily  seen  from  the  above  diagram  that  the  dis- 
covery of  the  Condylarthra  was  an  important  event  in  the  history 
of  our  knowledge  of  this  subject.  This  suborder  of  the  Lower 
Eocene  epoch  stands  to  the  placental  Mammalia  in  the  same  rela- 
tion as  the  Theromorphous  order  does  to  the  reptilian  orders.  It 
generalizes  the  characteristics  of  them  all,  and  is  apparently  the 
parent  stock  of  all,  excepting,  perhaps,  the  Cetacea.  The  dis- 
covery of  the  extinct  Bunotherian  suborders  united  together  in- 
separably the  clawed  orders,  excepting  the  bats ;  while  the  extinct 
order  Amblypoda  is  the  ancestor  of  the  most  specialized  of  the 
Ungulates,  the  odd-  and  even-toed  Diplarthra. 

The  characters  of  the  skeleton  of  the  order  Monotremata  show 
that  it  is  nearest  of  kin  to  the  Reptilia,  and  many  subordinate 


*  Except  Erinaceus. 

f  With  the  suborders  Insectivora,  Oreodonta,  Taeniodonta,  and  Tillodonta. 

X  This  was  inadvertently  omitted  in  the  original.     (Ed.  1886.) 


34:4:        THE   STRUCTURAL  EVIDENCE   OF  EYOLUTIOX. 

characters  point  to  tlie  Theromorplia  as  its  ancestral  source.*  In 
the  general  characters  the  Marsupialia  naturally  follow  in  a  rising 
scale,  as  proved  by  the  increasing  perfection  of  the  reproductive 
system.  The  Monodelphia  follow  with  improvements  in  the  re- 
productive system  and  the  brain,  as  indicated  in  the  table  already 
given.  The  oldest  Monodelphia  were,  in  respect  to  the  structure 
of  the  brain,  much  like  the  Marsupialia,  and  some  of  the  existing 
orders  resemble  them  in  some  parts  of  their  brain-structure. 
Such  are  the  Condylarthra  and  Amblypoda  of  extinct  groups, 
and  the  Bunotheria,  Edentata,  Rodentia,  and  Chiroptera,  recent 
and  extinct.  The  characters  of  the  brains  of  Amblypoda  and  some 
Oreodonta  are,  in  their  superficial  characters,  even  inferior  to  ex- 
isting marsupials.  The  divided  uterus  of  the  recent  forms  named, 
also  gives  them  the  position  next  to  the  Marsupialia.  In  the  Car- 
nivora,  Hyracoidea,  and  Proboscidia,  a  decided  advance  in  both 
brain-structure  and  reproductive  system  is  evident.  The  hemi- 
spheres increase  in  size,  and  they  become  convoluted.  A  uterus 
is  formed,  and  the  testes  become  external,  etc.  In  the  Quadru- 
mana  the  culmination  in  these  parts  of  the  structure  is  reached, 
excepting  only  that,  in  the  lack  of  separation  of  the  genital  and 
urinary  efferent  ducts,  the  males  are  inferior  to  those  of  many  of 
the  Artiodactyla.  This  history  displays  a  rising  scale  for  the 
Mammalia. 

Looking  at  the  skeleton,  we  observe  the  following  successional 
modifications  :  f 

First,  as  to  the  feet,  and  (A)  the  digits.  The  Condylarthra 
have  five  digits  on  both  feet,  and  they  are  plantigrade.  This  char- 
acter is  retained  in  their  descendants  of  the  lines  of  Anthropoidea, 
Quadrumana,  and  Hyracoidea,  also  in  the  Bunotheria,  Edentata, 
and  most  of  the  Rodentia.  In  the  Amblypoda  and  Proboscidia 
the  palm  and  heel  are  a  little  raised.  In  the  Carnivora  and  Dip- 
larthra  the  heel  is  raised,  often  very  high,  above  the  ground,  and 
the  number  of  toes  is  diminished,  as  is  well  known,  to  two  in  the 
Artiodactyla  and  one  in  the  Perissodactyla.  (B)  The  tarsus  and 
carpus.  In  the  Condylarthra  the  bones  of  the  two  series  in  the 
carpus  and  tarsus  are  opposite  each  other,  so  as  to  form  continuous 
and  separate  longitudinal  series  of  bones.     This  continues  to  be 

*  "Proceedings  American  Philosoph.  Society,"  18S4,  p.  43. 
f  See  the  evidence  for  evolution  in  the  history  of  the  extinct  Mammalia.     "  Pro- 
ceeds. Araer.  Assoc.  Adv.  Science,"  1883. 


PLATE  XVII. 


346        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION". 

the  case  in  the  Hyracoidea  and  many  of  the  Quadrumana,  but  in 
the  anthropoid  apes  and  man  the  second  row  is  displaced  inwards 
so  as  to  alternate  with  the  first  row,  thus  interrupting  the  series  in 
the  longitudinal  direction,  and  forming  a  stronger  structure  than 
that  of  the  Condylarthra.  In  the  Bunotherian  Rodent  and  Eden- 
tate series,  the  tarsus  continues  to  be  without  alternation,  as  in 
the  Condylarthra,  and  is  generally  identical  in  the  Carnivora.  In 
the  hoofed  series  proper  it  undergoes  change.  In  the  Proboscidia 
the  carpus  continues  linear,  while  the  tarsus  alternates.  In  the 
Amblypoda  the  tarsus  alternates  in  another  fashion,  and  the  car- 
pal bones  are  on  the  inner  side  linear,  and  on  the  outer  side  alter- 
nating. The  complete  interlocking  by  universal  alternation  of  the 
two  carpal  series  is  only  found  in  the  Diplarthra.  (C)  As  to  the 
ankle-joint.  In  most  of  the  Condylarthra  it  is  a  flat  joint  or  not 
tongued  or  grooved.  In  most  of  the  Carnivora,  in  a  few  Rodentia, 
and  in  all  Diplarthra,  it  is  deeply  tongued  and  grooved,  forming  a 
more  perfect  and  stronger  joint  than  in  the  other  orders,  where 
the  surfaces  of  the  tibia  and  astragalus  are  flat.  (D)  In  the  high- 
est forms  of  the  Rodentia  and  Diplarthra  the  fibula  and  ulna  be- 
come more  or  less  co-ossified  with  the  tibia  and  radius,  and  their 
middle  portions  become  attenuated  or  disappear. 

Secondly,  as  regards  the  vertebras.  The  mutual  articulations 
(zygapophyses)  in  the  Condylarthra  have  flat  and  nearly  horizon- 
tal surfaces.  In  higher  forms,  especially  of  the  ungulate  series, 
they  become  curved,  the  posterior  turning  upward  and  outward, 
and  the  anterior  embracing  them  on  the  external  side.  In  the 
higher  Diplartha  this  curvature  is  followed  by  another  curvature 
of  the  postzygapophysis  ujDward  and  outward,  so  that  the  vertical 
section  of  the  face  of  this  process  is  an  S.  Thus  is  formed  a  very 
close  and  secure  joint,  such  as  is  nowhere  seen  in  any  other 
Vertebrata. 

Thirdly,  as  regards  the  dentition.  Of  the  two  tjipes  of  Mono- 
tremata,  the  Tachyglossidse  and  the  Platypodid£e,  the  known  gen- 
era of  the  former  possess  no  teeth,  and  the  known  genus  of  the 
latter  possesses  only  a  single  corneous  epidermic  grinder  in  each 
jaw.  As  the  Theromorphous  reptiles  from  which  these  are  de- 
scended have  well-developed  teeth,  their  condition  is  evidently  one 
of  degeneration,  and  we  can  look  for  well-toothed  forms  of  Mono- 
tremata  in  the  beds  of  the  Triassic  and  Jurassic  periods.  Perhaps 
some  such  are  already  known  from  jaws  and  teeth.  In  the  mar- 
supial order  we  have  a  great  range  of  dental  structure,  which  almost 


EYOLUTIOISr   OF  THE   VERTEBRATA.  347 

epitomizes  that  of  the  Monodelph  orders.  The  dentition  of  the 
carnivorous  forms  is  creodont ;  that  of  the  kangaroos  is  perisso- 
dactyle,  and  that  of  the  wombats  is  rodent.  Other  forms  repeat 
the  Insectivora.  I  therefore  consider  the  phicental  series  espe- 
cially. I  have  already  shown  that  the  greater  number  of  the  types 
of  this  series  have  derived  the  characters  of  their  molar  teeth  from 
the  stages  of  the  following  succession.  First,  a  simple  cone  or 
reptilian  crown,  alternating  with  that  of  the  other  jaw.  Second, 
a  cone  with  lateral  denticles.  Third,  the  denticles  to  the  inner 
side  of  the  crown  forming  a  three-sided  prism,  with  tritubercular 
apex,  which  alternates  with  that  of  the  opposite  jaw.  Fourth, 
development  of  a  heel  projecting  from  the  posterior  base  of  the 
lower  jaw,  which  meets  the  crown  of  the  superior,  forming  a 
tubercular-sectorial  inferior  molar.  From  this  stage  the  carnivo- 
rous and  sectorial  dentition  is  derived,  the  tritubercular  type  being 
retained.  Fifth,  the  development  of  a  posterior  inner  cusp  in  the 
superior  molar,  and  the  elevation  of  the  heel  in  the  inferior  molar, 
with  the  loss  of  the  anterior  inner  cusp.  Thus  the  molars  become 
quadritubercular,  and  opposite.  This  is  the  type  of  many  of  the 
Taxeopoda,  including  the  Quadrumana  and  Insectivora  as  well  as 
the  inferior  Diplarthra.  The  higher  Taxeopoda  (Hyracoidea)  and 
Diplarthra  add  various  complexities.  Thus  the  tubercles  become 
flattened  and  then  concave,  so  as  to  form  Vs  in  the  section  pro- 
duced by  wearing  ;  or  they  are  joined  by  cross- folds,  forming  vari- 
ous patterns.  In  the  Proboscidia  the  latter  become  multii^lied  so 
as  to  produce  numerous  cross-crests. 

The  dentition  of  some  of  the  Sirenia  is  like  that  of  some  of 
the  Ungulata,  especially  of  the  suilline  group,  while  in  others  the 
teeth  consist  of  cvlinders.  In  the  Cetacea  the  molars  of  the  old- 
est  (Eocene  and  Miocene)  types  are  but  two-rooted  and  com- 
pressed, having  much  the  form  of  the  premolars  of  other  Mam- 
malia. In  existing  forms  a  few  have  simple  conical  teeth,  while 
in  a  considerable  number  teeth  are  entirely  wanting. 

A  review  of  the  characters  of  the  existing  Mammalia  as  com- 
pared with  those  of  their  extinct  ancestors  displays  a  great  deal 
of  improvement  in  many  ways,  and  but  few  instances  of  retro- 
gression. The  succession  in  time  of  the  Monotremata,  the  Mar- 
supialia,  and  the  Monodelphia,  is  a  succession  of  advance  in  all 
the  characters  of  the  soft  parts  and  of  the  skeleton  which  define 
them  (see  table  of  classification).  As  to  the  monotremes  them- 
selves, it  is  more  than  probable  that  the  order  has  degenerated  in 


348        THE   STRUCTURAL  EVIDENCE   OF  EVOLUTION. 

some  res]3ects  in  producing  the  existing  types.  The  history  of  the 
Marsupialia  is  not  made  out,  but  the  earliest  forms  of  which  we 
know  the  skeleton,  Polymastodon  (Cope)  of  the  Lower  Eocene,  is  as 
specialized  as  the  most  specialized  recent  forms.  The  dentition  of 
the  Jurassic  forms,  Plagiaulax,  etc.,  is  quite  specialized  also,  but 
not  more  so  than  that  of  the  kangaroos.  The  premolars  are  more 
specialized,  the  true  molars  less  specialized  than  in  those  animals. 

Coming  to  the  Monodelphia,  the  increase  in  the  size  and  com- 
plication of  the  brain,  both  of  the  cerebellum  and  the  hemi- 
spheres, is  a  remarkable  evidence  of  advance.  But  one  retro- 
gressive line  in  this  respect  is  known,  viz.,  that  of  the  order 
Amblypoda,*  where  the  brain  has  become  relatively  smaller  with 
the  passage  of  time.  The  successive  changes  in  the  structure  of 
the  feet  are  all  in  one  direction,  viz.,  in  the  reduction  of  the 
number  of  the  toes,  the  elevation  of  the  heel,  and  the  creation  of 
tongue  and  groove  joints  where  plain  surfaces  had  previously  ex- 
isted. The  diminution  in  the  number  of  toes  might  be  regarded 
as  a  degeneracy,  but  the  loss  is  accompanied  by  a  proportional 
gain  in  the  size  of  the  toes  that  remain.  In  every  respect  the 
progressive  change  in  the  feet  is  an  advance.  In  the  carpus  and 
tarsus  we  have  a  gradual  rotation  of  the  second  row  of  bones  on 
the  first,  to  the  inner  side.  In  the  highest  and  latest  orders  this 
process  is  most  complete,  and,  as  it  results  in  a  more  perfect  me- 
chanical arrangement,  the  change  is  clearly  an  advance.  The 
same  progressive  improvement  is  seen  in  the  development  of  dis- 
tinct facets  in  the  cubito-carpal  articulation,  and  of  a  tongue  and 
groove  (^*  in tertrochlear  crest  ")  in  the  elbow-joint.  In  the  ver- 
tebrae the  development  of  the  interlocking  zygapophysial  articula- 
tions is  a  clear  advance. 

Progress  is  generally  noticeable  in  the  dental  structures  ;  for, 
unlike  the  marsupial  line,  the  earliest  dentitions  are  the  most 
simple,  and  the  later  the  more  complex.  Some  of  the  types  re- 
tain the  primitive  tritubercular  molars,  as  the  Centetidae,  shrews 
and  some  lemurs,  and  many  Carnivora,  but  the  quadritubercular 
and  its  derivative  forms  are  by  far  the  most  common  type  in  the 
recent  fauna.  The  forms  that  produced  the  complicated  modifica- 
tions in  the  Proboscidia  and  Diplarthra  appeared  latest  in  time, 
and  the  most  complex  genera.  Bos  and  Equus,  the  latest  of  all. 
The  extreme  sectorial  modifications  of  the  tritubercular  type,  as 


*  See  "Naturalist,"  Jan.,  1885,  p.  55. 


EVOLUTION   OF  THE   YERTEBRATA.  349 

seen  in  the  Hyaenidge  and  the  Felidae,  are  the  latest  of  their  line 
also. 

Some  cases  of  degeneracy  are,  however,  apparent  in  the  mono- 
delphous  Mammalia.  The  loss  of  pelvis  and  posterior  limbs  in 
the  two  mutilate  orders  is  clearly  a  degenerate  character,  since 
there  can  be  no  doubt  that  they  have  descended  from  forms 
with  those  parts  of  the  skeleton  present.  The  reduction  of  flexi- 
bility seen  in  the  limbs  of  the  Sirenia  and  the  loss  of  this  char- 
acter in  the  fore  limbs  of  the  Cetacea  are  features  of  degeneracy 
for  the  same  reason.  The  teeth  in  both  orders  have  undergone 
degenerate  evolution  ;  in  the  later  and  existing  forms  of  the  Ceta- 
cea even  to  extinction.  The  Edentata  appear  to  have  undergone 
degeneration.  This  is  chiefly  ajoparent  in  the  teeth,  which  are 
deprived  of  enamel,  and  which  are  wanting  from  the  premaxillary 
bone.  A  suborder  of  the  Bunotheria,  the  Tgeniodonta  of  the 
Lower  Eocene  period,  display  a  great  reduction  of  enamel  on  the 
molar  teeth,  so  that  in  much-worn  examjoles  it  appears  to  be 
wanting.  Its  place  is  taken  by  an  extensive  coat  of  cementum, 
as  is  seen  in  Edentata,  and  the  roots  of  the  teeth  are  often  un- 
divided as  in  that  order.  It  is  probable  that  the  Edentata  are  the 
descendants  of  the  Tseniodonta  by  a  process  of  degeneracy. 

Local  or  sporadic  cases  of  degenerate  loss  of  parts  are  seen  in 
various  parts  of  the  mammalian  series,  such  as  toothless  jMamma- 
lia  wherever  they  occur.  Such  are  cases  where  the  teeth  become 
extremely  simple,  as  in  the  honey-eating  marsupial  Tarsipes,  the 
carnivore  Proteles,  the  Pteropod  bats,  and  the  aye-aye.  Also  where 
teeth  are  lost  from  the  series,  as  in  the  canine  genus  Dysodus,  and 
in  man.  The  loss  of  the  hallux  and  pollex  without  corresponding 
gain  in  various  genera,  may  be  regarded  in  the  same  light. 

In  conclusion,  the  progressive  may  be  compared  with  the  re- 
trogressive evolution  of  the  Vertebrata,  as  follows  :  In  the  earlier 
periods  and  with  the  lower  forms,  retrogressive  evolution  pre- 
dominated. In  the  higher  classes  progressive  evolution  has  pre- 
dominated. When  we  consider  the  history  of  the  first  class  of 
vertebrates,  the  Tunicata,  in  this  respect,  and  compare  it  with 
that  of  the  last  class,  the  Mammalia,  the  contrast  is  very  great. 


PART   III. 

MECHAIs^IOAL  EYOLUTIOE". 


XII. 

THE    EELATION    OF    ANIMAL    MOTION    TO    ANIMAL 

EVOLUTION. 

To  explain  the  origin  of  variation  in  animal  structure  is,  par 
excellence,  the  object  of  the  doctrine  of  evolution.  There  can  be 
little  doubt  that  the  law  of  natural  selection  includes  the  cause  of 
the  preservation  of  certain  modifications  of  pre-existent  structure, 
in  preference  to  others,  after  they  have  been  brought  into  exist- 
ence. In  what  manner  or  by  what  process  the  growing  tissues  of 
young  animals  have  been  so  affected  as  to  produce  some  organ  or 
part  of  an  organ  which  the  parent  did  or  does  not  possess,  must 
be  explained  by  a  different  set  of  laws.  These  have  been  termed 
originative^  while  those  involved  in  natural  selection  are  restrictive 
only. 

I. 

Of  course  we  naturally  look  to  something  in  the  *^  surrounding 
circumstances"  in  which  a  plant  or  animal  is  placed,  or  its  "en- 
vironment," as  the  most  probable  stimulant  of  change  of  its  char- 
acter, because  we  know  that  such  beings  are  totally  dependent  on 
cosmic  and  terrestrial  forces  for  their  sustenance  and  preservation. 
The  difficulty  has  been  to  connect  these  forces  with  change  of 
structure  SLS  originative ;  to  show  their  operation  as  multiplying, 
restricting  or  destroying  organisms  already  in  existence  is  compar- 
atively easy.  This  difficulty  is  partially  due  to  the  fact  that  such 
modifications  must  be  realized  during  a  limited  portion  of  the  life 
of  an  animal  at  least ;  that  is,  during  the  period  of  growth,  when 
it  is  not  at  all  or  but  little  subject  to  the  influence  of  external  en- 
vironment, but  is  usually  protected  or  supported  by  the  parent. 

That  the  environment  and  changes  in  it  affect  the  movements 


RELATION  OF  ANIMAL  MOTION  TO  ANIMAL  EVOLUTION.   351 

of  plants  and  animals  is  clear  enough.  The  potency  of  such 
changes  may  be  read  in  the  physical  history  of  the  earth.  A  long 
series  of  modifications  preceded  the  advent  of  life  upon  it,  and 
change,  both  gradual  and  sudden,  has  been  exhibited  in  the  con- 
figuration and  climate  of  all  portions  of  the  surface  of  the  globe 
since  that  period.  Animals  have  again  and  again  been  called 
upon  to  face  new  conditions,  and  myriads  of  species  have  fallen 
victims  to  the  inflexibility  of  their  organization  which  has  pre- 
vented adaptation  to  new  surroundings.  But  it  is  evident  that  if 
change  of  environment  has  had  any  influence  in  the  progress  of 
evolution,  it  has  not  been  alone  destructive.  It  has  preceded  life 
as  well  as  death,  and  has  furnished  the  stimulus  to  beings  capable 
of  change,  while  it  has  destroyed  those  which  were  incapable  of 
it.  It  is  a  truism  that  change  of  physical  conditions  has  preceded 
all  great  faunal  changes,  and  that  the  necessity  for  new  mechanism 
on  the  part  of  animals  has  always  preceded  the  appearance  of  new 
structure  in  geologic  times. 

The  embryology  and  paleontology  of  vertebrated  animals  show 
that  the  primary  steps  in  the  progress  of  this  branch  of  the  animal 
kingdom  are  marked  by  the  successive  changes  in  the  structure  of 
the  circulatory  system.  First  we  have  the  various  mechanical 
methods  for  the  aeration  of  blood  in  a  watery  medium  ;  the  result 
being  a  fluid  whose  metamorphosis  in  nutrition  produces  no  heat. 
After  the  fishes  followed  Batrachia,  the  earliest  air-breathers, 
whose  long  tarriance  to-day  in  early  aquatic  stages  is  an  epitome 
of  the  necessarily  *' amphibious"  character  of  air-breathing  verte- 
brate life,  when  land  and  fresh  water,  in  constantly  changing 
areas,  were  rising  and  separating  from  the  universal  ocean.  The 
successive  disappearances  of  the  traces  of  the  fish  type  of  circula- 
tion in  Batrachia  and  reptiles,  are  familiar  facts  ;  and  the  exclu- 
sion of  the  unaerated  blood  from  the  systemic  circulation  in  the 
birds  and  mammals  marks  the  increase  of  general  temperature 
which  gives  those  classes  one  of  their  claims  to  sui)eriority. 

The  appearance  of  land  of  course  furnished  the  opportunity 
for  aquatic  animals  to  assume  a  terrestrial  life.  Marine  animals 
which  had  acquired  the  habit  of  gulping  air  from  the  surface, 
which  some  of  them  now  possess,  perhaps  because  its  richness  in 
oxygen  produced  an  agreeable  exaltation  or  intoxication,  would 
not  find  visits  to  the  land  difficult.  And  this  would  naturally 
follow  the  necessity  of  escape  from  aquatic  enemies,  or  the  search 
for  new  supplies  of  food. 


352  MECHANICAL  EVOLUTION. 

In  fine,  it  requires  little  argument  to  sliow  that  the  enyiron- 
ment  has  had  in  the  past,  as  in  the  present,  a  primary  influence 
over  the  movements  of  animals. 

II. 

I  will  now  endeavor  to  exhibit  some  reasons  for  believing  that 
the  movements  of  animals  affect  their  structure  directly. 

There  are  two  alternative  propositions  expressive  of  the  rela- 
tions of  the  structures  of  animals  to  their  uses.  Either  the  use 
or  attempt  to  use  preceded  the  adaptive  structure,  or  else  the 
structure  preceded  and  gave  origin  to  the  use.  The  third  alter- 
native, that  use  and  structure  came  into  being  independently  of 
each  other,  is  too  improbable  for  consideration  in  the  present 
article.  Many  facts  render  the  first  of  these  propositions  much 
the  more  probable  of  the  two. 

A  general  ground  for  suspecting  that  movement  affects  struct- 
ure is  the  fact  well  known  to  systematic  zoologists,  that  adaptive 
characters  are  the  least  reliable  in  systematic  classification,  i.  e., 
are  the  most  variable.  What  we  call  adaptive  characters  are 
those  whose  teleological  significance  we  can  most  easily  perceive  ; 
those  whose  uses  are  at  the  present  time  most  obvious.  System- 
atists  habitually  fall  back  on  characters  which  are  apparently  the 
least  related  to  the  ordinary  necessities  of  the  life  of  the  animal, 
and  this  not  from  any  theoretical  considerations,  but  because  such 
characters  are  found  to  be  the  most  constant.  This  is  a  very  sig- 
nificant fact,  showing  as  it  does  that  it  is  the  adaptive  structures 
which  are  undergoing  modification  to-day.  And  this  truth  can 
doubtless  be  discerned  in  all  past  ages,  for  many  of  the  structures 
which  are  not  now  more  related  to  the  needs  of  an  animal  than 
many  others  might  be,  were  at  one  time  most  essential  to  its  well- 
being,  or  necessarily  related  to  its  environment.  Such  are  the 
structural  characters  of  the  heart  and  arteries  already  enumerated. 
There  seems  to  be  no  reason  why  all  Vertehrata  might  not  exist 
with  equal  comfort  and  success  at  the  present  if  possessed  of  a 
uniform  organization  in  this  respect.  But  the  successive  modi- 
fications which  they  present  were,  in  past  ages,  most  intimately 
connected  with  the  progressive  changes  of  the  medium  in  which 
they  lived,  as  to  the  volume  of  oxygen  su23plied  for  respiration, 
as  compared  with  that  of  the  vapor  of  water,  carbonic  acid  gas, 
etc.  But  it  must  be  here  noted,  in  passing,  that  there  are  many 
structures  in  animals  which  have  never  been  adaptive,  but  which 


RELATION  OF  ANIMAL  MOTION  TO  ANIMAL  EVOLUTION.   353 

are  simjoly  due  to  excess  or  defect  of  nutrition  following  a  redis- 
tribution of  force.* 

The  most  direct  evidence  in  support  of  the  view  that  motion 
affects  structure  directly  is  to  be  found  in  the  well-known  phe- 
nomenon of  the  increase  of  the  size  and  power  of  all  organs  by 
use.  This  increase  is  limited  in  the  adult  animal  by  the  general 
fixity  of  all  the  organs,  so  that  one  of  them  cannot  be  developed 
beyond  a  certain  point  without  injury  to  others,  or  without  ex- 
hausting the  source  of  supply  of  nutritive  material  or  special  force  ' 
derived  from  other  organs.  The  syncope  of  the  gymnast  is  an 
illustration  of  the  natural  limitation  to  the  development  of  the  1 
muscular  system  which  proceeds  at  the  expense  of  the  digestive 
and  circulatory.  But  effort  and  exertion  may  become  a  habit  of 
mind,  which,  even  if  limited  in  its  executive  means,  is  probably  in- 
herited by  offspring  like  all  other  mental  traits.  Such  a  quality 
possessed  by  an  infant  or  child  doubtless  tells  on  the  growth  of  \ 
its  organs  during  their  plastic  stage,  and  produces  structure  by  \ 
growth  which  is  impossible  to  the  mature  body.f  And  no  one 
knows  as  yet  how  far  mental  bias  may  affect  the  nutrition  of  the 
parts  of  the  infant  in  utero.  Certain  it  is,  that  if  use  modifies 
nutrition  in  the  adult,  it  must  have  still  greater  influence  in  the 
young  ;  and  it  is  in  the  young  that  tlie  changes  which  constitute 
evolution  necessarily  appear. 

Change  of  structure  during  growth  is  accomplished  either  by 
addition  of  parts  (^^acceleration")  or  by  subtraction  of  parts 
("retardation"). 

Acceleration  is  produced  either  by  multiplication  of  parts  (as 
cells  or  segments)  already  present  (^Miomotopy "),  or  by  the 
transfer  of  parts  (cells)  from  one  part  of  the  organism  to  the 
other  (*^heterotopy  ").  Homotopy  or  repetition  is  the  usual  and 
normal  mode  of  acceleration  ;  it  may  proceed  by  an  "  exact  repeti- 
tion "  of  the  parts  already  existing,  as  in  the  simplest  animals  and 
plants  ;  or  the  new  parts  may  differ  from  the  old,  as  in  higher 
animals,  where  the  process  is  called  "modified  repetition."  Where 
new  forms  traverse  in  their  growth  all  the  stages  in  which  they 
previously  existed,  they  necessarily  present  at  each  stage  the  char- 
acters of  those  forms  which  have  remained  stationary  in  them,  and 
have  not  changed.     This  relation  of  "  exact  parallelism  "  is  the 


*  "Method  of  Creation,"  1871,  p.  23. 
f  In  raan  these  changes  are  chiefly  produced  in  the  brain. 
23 


354  MECHANICAL  EVOLUTION. 

result  of  the  simplest  form  of  evolution  or  ^^palingenesis."  When 
the  history  of  growth  of  an  advanced  form  does  not  show  an 
identity  between  its  stages  and  the  various  undeveloped  or  lower 
adult  types,  the  relation  is  termed  'Mnexact  parallelism,"  and  the 
type  of  development  ''  coenogenesis. '' 

Change  of  structure  is  seen  to  take  place  in  accordance  with 
the  mechanical  effect  of  three  forms  of  motion,  viz.:  hj  friction, 
pressure  and  strain.  Under  the  first  two,  epidermal  tissues  be- 
come both  dense  and  thick,  as  is  seen  on  the  palms  and  soles  of 
the  hands  and  feet,  and  in  corns.  There  is  no  doubt  that  strength 
of  the  teeth  is  intimately  connected  with  the  hardness  of  the 
food.  Density  of  osseous  tissue  and  the  coossification  of  parts  of 
the  skeleton,  are  directly  associated  with  the  force  and  duration 
of  muscular  contraction.  Pathology  abounds  in  illustrations  of 
the  determination  of  nutrition  to  new  localities  to  meet  the  exi- 
gencies and  demands  arising  from  new  stimuli.  It  is  only  neces- 
sary for  a  structure-producing  supply  of  nutritive  material  to  be 
habitually  determined  to  a  new  locality  by  oft-recurring  stimulus, 
for  the  movement  to  become  automatic  and  reflex  ;  and  such  a 
tendency  would  sooner  or  later  be  inherited,  and  produce  struct- 
ure in  the  growing  organism  of  the  young  to  a  degree  far  exceed- 
ing anything  that  is  possible  in  the  adult. 

In  view  of  the  above  considerations,  we  can  ascribe  an  exten- 
sive class  of  osseous  projections  at  points  of  muscular  insertion, 
to  the  strength  and  duration  of  muscular  contractions.  To  the 
same  cause  may  be  ascribed  various  anchyloses,  such,  for  instance, 
as  is  seen  in  the  foot  of  the  sloth.  Transverse  strains  or  their  ab- 
sence may  be  looked  upon  respectively  as  the  cause  of  the  hinge- 
like or  immovable  articulations  of  the  segments  of  the  limbs  of 
vertebrate  animals.  It  is  well  knoAvn  that  in  land  animals,  where 
easy  flexibility  of  the  limbs  is  essential  to  speed,  these  articula- 
tions are  highly  developed,  while  in  marine  animals,  where  the 
limbs  are  only  used  as  paddles,  they  are  almost  or  quite  in- 
flexible, and  the  extremities  of  the  bones  are  truncate.  In  the 
most  highly  organized  land  Mammalia,  the  tibio-tarsal  and  hu- 
mero-cubital  articulations  display  an  interlocking  or  tongue- 
and-groove  character.  The  same  thing  is  seen  in  the  ulno- 
radial  fixed  articulation  in  the  same  types.  These  arrangements 
are  especially  adapted  to  prevent  dislocation  by  side  strains, 
and  if  the  preceding  explanations  be  true,  this  structure  is 
a  corrugation   due   to   the   lateral   pressure   of    a   more   or  less 


RELATION  OF  ANIMAL  MOTION  TO  ANIMAL  EVOLUTION.   355 

convex  surface,  on  a  concave  one  which  embraces  it,  and  vice 
versa. 

In  the  circulatory  system,  pressure  has  doubtless  played  an  im- 
portant part.  Increased  oxygenation  of  blood,  the  necessary  con- 
sequence of  the  purification  of  the  atmosphere,  would  stimulate 
the  action  of  all  the  organs,  including  that  of  the  heart.  Greater 
pressure  on  its  walls  and  septa  w^ould  increase  their  size  and 
strength,  and  ultimately  close  such  foramina  as  were  not  in  the 
course  of  the  blood  current,  as  the  foramen  septi  ventriculorum 
of  reptiles,  and  the/,  ovale.  Increased  force  of  the  current  would, 
on  the  other  hand,  soon  cause  the  enlargement  of  one  or  other  of 
the  four  or  five  pairs  of  primary  aorta  bows,  and  develop  it  at  the 
expense  of  the  others,  until  finally  the  pre-eminence  of  one  chan- 
nel be  secured  and  the  aorta  be  the  result.  This  part  of  the  sub- 
ject might  be  prolonged  to  an  unlimited  extent,  but  the  above 
illustrations  must  suffice  to  indicate  the  meaning  of  my  proposi- 
tions. 

III. 

That  movements  change  the  environment  of  a  plant  or  an  ani- 
mal, or  parts  of  them,  is  obvious  enough.  If  we  consider  only 
the  reflex  class,  to  which  all  the  movements  of  plants  and  many 
of  those  of  animals  belong,  we  perceive  that  but  for  them  the  or- 
dinary functions  of  assimilation,  circulation,  etc.,  could  not  be 
performed  ;  there  would  be  no  change  in  the  contents  of  their 
tubes  and  cells,  and  the  environment  of  these  would  be  unaltered. 
But  when  we  view  the  movements  of  the  higher  animals,  w^e  j)er- 
ceive  the  immense  importance  of  the  powers  and  organs  of  move- 
ment as  a  factor  in  evolution.  It  may  be  safely  assumed  that, 
without  powers  of  designed  or  adaptive  movement,  life  would 
never  have  advanced  beyond  the  stage  presented  by  the  vegetable 
kingdom. 

The  stimuli  which  are  effective  in  animal  consciousness  are 
four,  viz.:  excessive  temperature,  hunger,  danger  from  enemies, 
and  the  reproductive  instinct.  These  prompt  to  the  movements 
which  we  observe  in  animals  in  a  wild  state,  and  without  which 
it  is  evident  that  the  animals  themselves  would  soon  cease  to 
exist. 

It  can  not  be  denied  that  organisms  which  are  incapable  of 
moving  from  place  to  place  in  search  of  food,  or  of  migration  to 
escape  vicissitudes  of  temperature,  are  much  more  completely  sub- 


356  '    MECHANICAL  EVOLUTION. 

ject  to  the  influences  of  their  environment  than  those  that  are  ca- 
l)able  cf  such  movement.  Hence  animals  are  much  more  inde- 
pendent of  the  supply  of  food  and  of  temperature  than  are  plants. 
Hence  also,  other  things  being  equal,  the  greater  the  powers  of 
motion,  the  greater  the  independence. 

Powers  of  movement  then  enable  animals  to  avoid  extremes 
of  climate  by  migrations  or  by  protective  arts.  They  enable  them 
to  procure  food  by  making  journeys  in  search  of  it,  and  by  all 
methods  of  capturing  it.  They  furnish  the  agent  of  active  defense 
against  enemies,  and  of  successfully  reproducing  their  kind. 

When,  through  changes  of  level  of  the  earth's  surface,  drought 
has  overtaken  a  region,  animals  capable  of  the  necessary  migrations 
have  escaped.  When  an  irruption  of  destructive  animal  enemies 
has  threatened  an  animal  population  with  death,  those  members 
of  it  whose  strength  or  speed  insured  them  safety,  were  the  sur- 
vivors. When  land  has  been  encroached  upon  by  water  to  such  a 
degree  as  to  bring  starvation  on  its  animal  inhabitants,  those  which 
could  fly  or  swim  have  sought  new  localities. 

Since  all  food-supply,  as  well  as  the  ability  to  obtain  food,  is 
dependent  on  temperature,  those  portions  of  the  organism  which 
furnish  means  of  resistance  to  climatic  vicissitudes  have  the 
deepest  significance  in  the  life-history  of  any  division  of  ani- 
mals. 

The  organs  of  circulation  and  motion  are  generally  recognized 
as  primary  in  the  classification  of  Vertehrata.  All  situations  where 
animal  life  is  permitted  by  climate,  support  vegetable  life  also  ;  so 
each  of  the  primary  divisions  of  animals  presents  types  adapted  to 
the  use  of  all  kinds  of  food  ;  herbivorous,  omnivorous,  and  carniv- 
orous. Accordingly,  it  has  been  found  that  dental  and  other 
structures  connected  with  digestion  define  divisions  of  secondary 
value  and  minor  extent.  Paleontology  shows  that  the  origin  of 
such  divisions  is  of  later  date  than  that  of  the  great  classes  first 
mentioned  ;  and  each  of  the  latter  has  in  its  day  been  modified  in 
the  subordinate  directions  indicated  bv  the  teeth  and  beak.  But 
here  also  organs  of  movement  are  of  great  importance  ;  so  that  the 
herbivorous  and  carnivorous  types  at  least,  have  ever  in  land  ani- 
mals (reptiles,  birds  and  mammals)  been  characterized  by  the 
structure  of  their  feet  also. 


RELATION  OF  ANIMAL  MOTION  TO  ANIMAL  EVOLUTION,   357 


IV. 

It  has  been  maintained  above,  that  environmeut  governs  the 
movements  of  animals,  and  that  the  movements  of  animals  then 
alter  their  environment.  It  has  also  been  maintained  that  the 
movements  of  animals  have  modified  their  structure  so  as  to  render 
them  more  or  less  independent  of  their  environment.  The  history 
of  animal  life  is  in  fact  that  of  a  succession  of  conquests  over  the 
restraints  imposed  by  physical  surroundings.  Man  has  attained 
to  a  wonderful  degree  of  emancipation  from  the  iron  bonds  that 
confine  the  lower  organisms. 

It  becomes  then  all  important  to  examine  into  the  elements  in- 
volved in  animal  movements. 

These  are  of  the  two  classes,  reflex  and  conscious.  To  the 
former  belongs  the  accelerated  activity  of  muscular  action  and 
circulation,  inferred  to  have  accompanied  increase  in  the  percent- 
age of  oxygen  in  the  atmosphere,  during  the  periods  of  geological 
time.  To  the  consciously  performed  acts  belong  all  those  due  to 
states  of  pain  or  pleasure  in  animals  ;  such  as  are  excited  by  the 
four  classes  of  stimuli  already  mentioned. 

Doubtless  physical  changes  in  the  surrounding  medium  have 
always  produced  new  reflex  movements  in  animals,  and  have  been 
a  first  element  in  evolution.  Such  has  been  the  immediate  cause 
of  change  of  structure  m  plants,  and  in  animals  so  far  as  they  are 
unconscious.  But  consciousness  brings  with  it  limitless  possibili- 
ties, since  it  places  an  animal  in  contact  with  innumerable  stimuli 
which  leave  unconscious  beings  unaffected.  All  the  causes  which 
2)rovoke  the  movements  of  higher  animals  are  appeals  to  conscious- 
ness, and  the  consequences  due  to  movements  of  such  beings  have 
only  been  possible  through  consciousness. 

It  is  evident  then  that  sensibility  to  impressions  has  been  the 
prime  essential  to  the  acquisition  of  new  movements,  and  hence 
of  new  structure,  other  things  being  equal.  Another  essential,  not 
less  important,  has  been  memory ;  because  without  this  faculty, 
experience,  and  hence  education  and  the  acquisition  of  habits  of 
movement,  are  not  possible. 

The  ascending  development  of  the  bodily  structure  in  higher 
animals  has  thus  been,  m  all  probability,  a  concomitant  of  the  evo- 
lution of  mind,  and  the  progress  of  the  one  has  been  dependent 
in  an  alternating  way  on  the  progress  of  the  other.  The  develop- 
ment of  mind  has  secured  to  animals  the  greatest  degree  of  inde- 


358  MECHANICAL  EVOLUTION. 

pendence  of  their  enyironment  of  whicli  tbey  are  capable.  The 
first  important  acquisition  leading  to  this  end  was  aerial  respira- 
tion ;  the  second,  rapid  nutrition  by  hot  blood.  And  as  essential 
to  tlie  production  and  preservation  of  these,  improvements  in 
organs  of  movement  have  been  superadded  to  every  successive 
type  of  life. 

Consciousness  remains  as  the  unresolvable  factor  in  the  process ; 
as  at  once  the  measure  of,  and  respondent  to  a  large  class  of  phe- 
nomena. 


XIIL 

ON  THE  TRITUBERCULATE  TYPE  OF  MOLAR  TOOTH 

m  THE  MAMMALIA. 

It  is  now  apparent  that  the  type  of  superior  molar  tooth  which 
predominated  during  the  Puerco  epoch  was  triangular  or  trituber- 
cular ;  that  is,  with  two  external  and  one  internal  tubercles.* 
Thus,  of  sixty-seven  species  of  placental  Mammalia  of  which  the 
superior  molars  are  known,  all  but  four  have  three  tubercles  of  the 
crown,  and  of  the  remaining  sixty-five,  all  are  triangular,  except- 
ing those  of  three  species  of  Periptychus,  and  three  allied  forms, 
which  have  a  small  supplementary  lobe  on  each  side  of  the  median 
principal  inner  tubercle,  f 

This  fact  is  important  as  indicating  the  mode  of  development 
of  the  various  types  of  superior  molar  teeth,  on  which  we  have  not 
heretofore  had  clear  light.  In  the  first  place,  this  type  of  molar 
exists  to-day  only  in  the  insectivorous  and  carnivorous  Marsupialia  ; 
in  the  Creodonta,  and  the  tubercular  molars  of  such  Carnivora  as 
possess  them  (excepting  the  plantigrades).  In  the  L^ngulates  its 
persistence  is  to  be  found  in  the  molars  of  the  Coryphodontidae  of 
the  Wasatch,  and  Dinocerata  of  the  Bridger  Eocenes.  In  later 
epochs  it  is  occasionally  seen  only  in  the  last  superior  molar. 

It  is  also  evident  that  the  quadritubercular  molar  is  derived 
from  the  tritubercular  by  the  addition  of  a  lobe  of  the  inner  part 
of  a  cingulum  of  the  posterior  base  of  the  crown.  Transitional 
states  are  seen  in  some  of  the  Periptychidae  {Anisonchiis),  and  in 
the  sectorials  of  the  Procyonidae. 

The  tritubercular  or  triangular  superior  molar  is  associated 
with  a  corresponding  form  of  the  anterior  part  of  the  inferior 
molar.     This  kind  of  inferior  molar  X  I  have  called  the  tubercular 


*  See  "  American  Naturalist,"  April,  1883,  p.  407. 

f  This  type  is  tlierefore  only  an  extension  of  the  tritubercular.     (Ed.  18S6.) 
X  See  Report  G.  M.  Wheeler,  D.  Chief  of  Engineers  on  Explor.  Surv.  W.  100th 
Mer.,  vol.  iv,  pt.  ii ;  on  the  Creodonta, 


360 


MECHAII^ICAL  EVOLUTION. 


sectorial,  and  is  very  variable  as  to  the  degree  of  development  of 
the  sectorial  cutting  edge.  The  anterior  triangle  is  formed  by 
the  connection,  by  angle  or  crest,  of  the  median  and  anterior  in- 
ternal crests  with  the  anterior  external.  Its  primitive  form  is 
seen  in  Didelphys,  Pelycodus,  Pantolambda,  and  the  Amblypoda 
generally  ;  in  Centetes  and  Talpa ;  and  in  its  sectorial  form,  in 
Styi^olophus  and  Oxysena,  etc. 


Fia,  64. — StypolopJim  ivMtim  Cope,  sTcull  two  thirds  natural  size.  A  Creodont 
from  the  Wasatch  Eocene,  displaying  well  the  tritubcrcular  superior,  and  the  tubercu- 
lar-sectorial  inferior  molars. 


The  mechanical  action  of  such  teeth  is  as  follows  :  Of  course, 
it  results  from  the  form  of  the  superior  molars  that  the  spaces  be- 
tween them  are  wedge-shaped,  the  apex  external,  the  base  open- 


TRITUBERCULATE  TYPE  OF  MOLAR  TOOTH.  361 

ing  to  the  palate.  The  base  of  the  triangular  section  of  the  an- 
terior part  of  the  inferior  molar  is  interior,  and  the  apex  exterior, 
and  when  the  jaws  are  closed  this  triangular  prism  exactly  fits 
the  space  between  the  superior  molars.  The  lower  heel  of  the  in- 
ferior molar  receives  the  impact  of  the  crown  of  the  superior 
molar.  Thus  the  oblique  edges  of  the  inferior  triangle  shear  on 
the  edges  of  two  adjacent  superior  molars.  The  anterior  parts  of 
the  inferior  molars,  and  the  superior  molars,  form  an  alternate 
dental  series  as  distinguished  from  the  prevalent  opposed  denti- 
tion of  most  Mammalia.  In  so  far  it  resembles  the  reptilian 
dentition. 

This  primitive  dentition  has  been  modified  in  two  directions, 
viz.,  to  form  the  grinding  and  the  sectorial  dentitions.  As 
already  remarked,  the  superior  molars  gradually  acquire  a  pos- 
terior internal  lobe,  which  produces  the  quadrituberculate  type. 
This,  lobe,  by  opposing  the  anterior  internal  lobe  of  the  next  pos- 
terior inferior  molar,  precludes  the  entrance  of  the  anterior  trian- 
gle of  the  latter  between  the  two  superior  molars.  Hence  we  find 
in  the  types  which  possess  quadri tubercular  superior  molars,  that 
the  anterior  triangle  of  the  inferior  molar  is  not  elevated,  if  pres- 
ent, as,  for  instance,  in  Rhinocerus.  It  is,  however,  more  fre- 
quently atrophied,  and  disappears,  contributing  to  form  the  in- 
ferior quadritubercular  molar  so  well  known. 

On  the  other  hand,  as  I  have  pointed  out,*  the  anterior 
internal  cusp  of  the  triangle  of  the  inferior  molar  may  be  more 
developed  antero-posteriorly,  giving  the  antero-internal  edge  of 
the  triangle  much  greater  obliquity  than  the  postero-internal. 
In  correspondence  with  this  modification,  the  superior  triangular 
molar  loses  its  equilateral  character  by  the  more  anterior  position 
of  its  internal  angle,  thus  elongating  the  posterior  internal  side  of 
the  crown.  The  latter  thus  fits  the  corresponding  form  of  the 
triangle  of  the  inferior  molar,  forming  with  it  the  shear  of  the 
sectorial  tooth. 

In  a  former  article,  ^^On  the  Homologies  of  the  Molar  Teeth," 
etc.,  I  traced  the  modifications  of  the  superior  and  many  of  the 
inferior  molars  of  the  ungulate  mammals  to  a  parent  quadrituber- 
culate type.     In  a  subsequent  essay  f  I  traced  the  origin  of  the 


*  On  the  origin  of  the  sectorial  tooth  of  the  Carnivora,  "  American  Naturalist," 
1875. 

f  "Journal  Academy  Natural  Sciences,"  Philadelphia,  March,  18Y4. 


362 


MECHANICAL  EVOLUTION. 


inferior  sectorial  to  a  primitive  five-tubercled,  or  '^tubercular 
sectorial"  type.  Farther  than  this  I  did  not  go,  and  made  no 
attempt  to  derive  the  few  cases  of  triangular  superior  molars  then 
known,  nor  the  type  of  the  superior  sectorial.  The  revelations  of 
the  Puerco  fauna  show  that  the  superior  molars  of  both  ungulate 
and  unguiculate  Mammalia  have  been  derived  from  a  tritubercular 


Fig.  65. — Deltatherium  fnndaminis  Cope,  skull  and  ramus  mandibuli,  two  thirds 
natural  size,  from  the  Puerco  beds  of  New  Mexico.  Fitrs.  a,  i,  c,  from  one  individual. 
Fig,  d^  from  a  second  animal.  Fig.  a,  right  side  of  cranium  ;  J,  palate  from  below  ;  c, 
mandible  part,  from  above ;  d^  left  ramus,  outer  side.  From  the  Eeport  U.  S.  Geol. 
Surv.  Terrs.,  vol.  iii. 


Original. 


type  ;  and  that  the  inferior  true  molars  of  both  have  been  derived 
from  a  "  tubercular  sectorial "  type.  Shall  we  look  for  the  origin 
of  the  latter  in  a  tritubercular  tooth  also,  i.  e.,  tubercular  sec- 
torial without  heel ;  and  will  the  crowns  of  the  true  molars  of  the 
primitive  mammals  alternate  with,  instead  of  opjDose  each  other  ? 
This  is  a  probable  result  of  future  discovery. 


xiy. 

THE  ORIGIN   OF  THE   SPECIALIZED  TEETH  OF  THE 

CARJSTIVORA. 

The  specially  developed  teeth  of  the  Carnivora  are  the  canines 
and  sectorials.  The  former  are  large  in  many  orders  of  Mam- 
malia,  and  their  origin  is  probably  to  be  sought  among  the  Thero- 
morphous  reptilia,*  as  Clepsydrops  and  Deuterosaxirus,  if  not  in 
still  lower  types.  The  successive  modifications  of  form  which 
have  resulted  in  the  existing  sj)ecialized  single  lower  sectorial 
tooth  of  the  FelidcB  have  been  already  pointed  out.f  They  were 
shown  to  consist  in  the  gradual  obliteration  of  the  internal  and 
posterior  tubercles,  and  the  enlargement  of  the  external  anterior 
tubercle  in  connection  with  an  additional  anterior  tubercle.  The 
modification  in  the  character  of  the  dentition,  taken  as  a  whole, 
was  shown  to  consist  in  the  reduction  in  the  number  of  teeth,  un- 
til in  Felis,  etc.,  we  have  almost  the  entire  function  of  the  molar 
series  confined  to  a  single  large  sectorial  in  each  jaw. 

Observation  on  the  movements  of  the  jaws  of  Carnivora  shows 
that  they  produce  a  shearing  motion  of  the  inferior  on  the  su- 
perior teeth.  This  is  quite  distinct  from  the  sub-horizontal 
movement  of  Ruminants,  or  the  vertical  motion  of  hogs  and 
monkeys.  Examination  of  the  crowns  of  the  sectorials  shows 
that  the  inner  side  of  the  superior,  and  the  external  side  of  the 
inferior,  are  worn  in  the  process  of  mastication.  The  attempt  to 
cut  the  tough  and  stringy  substances  found  in  animal  bodies  is 
best  accomplished  by  the  shearing  of  the  outer  edge  of  the  lower 
molar  on  the  inner  edge  of  the  external  tubercles  of  the  superior 
molar,  in  an  animal  with  simple  tubercular  teeth.  The  width  of 
the  mandible  is  too  great  to  allow  the  inferior  teeth  to  shear  on 
the  inner  edge  of  the  inner  tubercles  of  the  superior  series.     The 


*  "  American  Naturalist,"  1878,  p.  829. 

f  Cope,  "Proceedings  Academy  Philada.,"  1875,  p.  22. 


PLATE  XVIII. 


Hycenodon  horridus  Leidy,  skull  one  half  natural  size.    From  the  White  River  formation 
of  Nebraska.    From  Leidy's  "  Extinct  Mammalia  of  Dakota  and  Nebraska." 


ORIGIN  OF  SPECIALIZED  TEETH  OF  THE  CARNIVORA.     365 

cusps  of  both  superior  and  inferior  teeth  engaged  in  this  process 
have  developed  in  elevation,  at  the  expense  of  those  not  engaged 
in  it,  viz. :  the  internal  cusps  of  the  same  teetli.  The  atrophy  of 
the  latter  can  not  have  been  due  to  friction,  since  the  internal 
cusps  of  the  inferior  series,  which  have  not  been  subjected  to  it, 
are  reduced  like  those  of  the  superior  sectorial,  which  have.  In- 
deed, it  is  possible  that  some  of  the  Creodonta,  the  carnivores  of 


Fig.  66. —  Oxymna  lupina  Cope,  jaws,  one  half  natural  size,  from  the  Wasatch  beds 
of  New  Mexico.  Fig.  a,  maxillary  bone  with  teeth,  from  below  ;  6,  last  superior  molar, 
from  behind.  Original ;  from  the  Eeport  U.  S.  G.  G.  Survey  W.  of  100th  Mer.,  G.  M. 
Wheeler. 

the  Lower  Eocene,  may  have  been  derived  from  ancestors  without 
or  with  rudi mental  inner  cusps.  In  any  case  the  effect  of  use  in 
lengthening  the  external  cusps  appears  to  have  operated  in  the 
Carnivora,  as  it  has  done  to  a  greater  degree  in  the  Uiigidata  ;  and 
the  lateral  vertical  wear  would  appear  to  have  resulted  in  the 
blade-form,  as  transverse  wear  in  the  Ungulates  has  resulted  in 
the  plane  grinding  surface. 

The  specialization  of  one  tooth  to  the  exclusion  of  others  as  a 
sectorial,  appears  to  be  due  to  the  following  causes.  It  is  to  be 
observed,  in  the  first  place,  that  when  a  carnivore  devours  a 
carcass,  it  cuts  off  masses  with  its  sectorials,  using  them  as 
shears.  In  so  doing  it  brings  the  part  to  be  divided  to  the  angle 
or  canthus  of  the  soft  walls  of  the  mouth,  which  is  at  the  front  of 
the  masseter  muscle.  At  this  point,  the  greatest  amount  of  force 
is  gained,  since  the  weight  is  thus  brought  immediately  to  the 
power,  which  would  not  be  the  case  were  the  sectorial  situated 
much  in  front  of  the  masseter.  On  the  other  hand  the  sectorial 
could  not  be  situated  farther  back,  since  it  would  then  be  inac- 
cessible to  a  carcass  or  mass  too  large  to  be  taken  into  the  mouth. 

The  position  of  the  sectorial  tooth  being  thus  shown  to  be  de- 


366 


MECHANICAL  EVOLUTION", 


pendent  on  that  of  the  masseter  muscle,  it  remains  to  ascertain  a 
probable  cause  for  the  relation  of  the  latter  to  the  dental  series  in 

modern  Carnivora.  Why,  for 
instance,  were  not  the  last 
molars  modified  into  sectorial 
teeth  in  these  animals,  as  in 
the  extinct  Hycenodon,  and 
various  Creodontaf  The  an- 
swer obviously  is  to  be  found 
in  the  development  of  the  pre- 
hensile character  of  the  canine 
teeth.  It  is  probable  that  the 
gape  of  the  mouth  in  the  Hyae- 
nodons  was  very  wide,  since  the 
masseter  was  situated  relative- 
ly far  posteriorly.  In  such  an 
animal  the  anterior  parts  of 
the  jaws  with  the  canines  had 
little  prehensile  power,  as  their  form  and  anterior  direction  also 
indicates.  They  doubtless  snapped  rather  than  lacerated  their 
enemies.     The  same  habit  is  seen  in  the  existing  dogs,  whose  long 


F  G.  67. — rrooelurvs  jalieni  Filh.,  two 
thirds  natural  size.  From  tlic  Phosphorites 
of  France.     From  Filhol. 


Fig.  68. — Dinidis  ajclops^  one  half  natural  size.      From  John  Day   Miocene  of 
Oregon.     Mus.  Cope.     From  vol.  iii,  U.  S.  Gcol.  Surv.  Terrs. 

jaws  do  not  permit  the  lacerating  power  of  the  canines  of  the 
Felidce,  though  more  effective  in  this  respect  than  those  of  the 
Hycenodons.  The  usefulness  of  a  lever  of  the  third  kind  depends 
on  the  approximation  of  the  power  to  the  weight ;  that  is,  in  the 


ORIGIN  OF  SPECIALIZED  TEETH  OF  THE  CARNIYORA.      367 


present  case,  the  more  anterior  the  position  of  the  masseter  muscle, 
the  more  effective  the  canine  teeth.  Hence  it  appears  that  the  rela- 
tion of  this  muscle  to  the  inferior  dental  series  depended  originally 
on  the  use  of  the  canines  as  prehensile  and  lacerating  organs,  and 
that  its  insertion  has  advanced  from  behind  forward  in  the  history 
of  carnivorous  types.  Thus  it  is  that  the  only  accessible  molars, 
the  fourth  above  and  the  fifth  below,  have  become  specialized  as 
sectorials,  while  the  fifth,  sixth,  and  seventh  have,  firstly,  remained 
tubercular  as  in  the  dogs,  or,  secondly,  have  been  lost,  as  in  hy- 
enas and  cats. 


XV. 

ox    THE    ORIGIN    OF    THE    FOOT    STRUCTURES    OF 

THE  UNGULATES. 

The  following  considerations  have  been  suggested  by  a  study 
of  the  primitive  types  of  the  odd-  and  even-toed  ungulates.  I 
first,  in  1874,  recorded  the  opinion  that  the  Mammalia  with  a 
reduced  number  of  digits  were  derived  from  pentadactyle  planti- 
grade types.*  The  ungulate  order  which  fulfills  this  requirement 
is  the  Amhlypoda,  and  from  them,  I  doubt  not,  both  the  Perisso- 
dactyla  and  Artiodactyla  have  arisen,  although  not  from  any  of 
the  genera  now  known.  Both  of  these  great  orders  display  a 
regular  diminution  in  the  number  of  the  digits  ;  in  the  former, 
by  reduction  and  extinction  on  both  sides  of  the  third  digit ;  in 
the  latter,  by  reduction  and  extinction  on  each  side  of  the  third 
and  fourth  digits.  Mr.  John  A.  Ryder  f  has  pointed  out  that 
reduction  in  digits  is  probably  directly  related  to  strains  and  im- 
pacts. He  reminds  us  that  the  anterior  digits  are  reduced  in 
Mammalia  of  unusual  scansorial  or  fossorial  powers  ;  while  in 
forms  which  display  powers  of  running,  the  reduction  is  seen  first 
in  the  posterior  feet,  which  j)ropel  the*  body  much  more  than  the 
fore  feet.  This  view  is  well  illustrated  in  the  Perissodactyle 
families,  the  majority  of  which  have  the  digital  formula  4 — 3. 

No  reason  has  ever  been  suggested,  so  far  as  I  am  aware,  in 
explanation  of  the  fact  that  one  series  of  ungulates  has  retained 
two  digits,  and  the  other  only  one  ;  that  is,  why  there  should 
have  been  two  kinds  of  digital  reduction  instead  of  one  kind.  In 
seeking  for  an  explanation,  we  will  remember  that  the  tarsus  in 
the  odd  or  single-toed  line  is  bound  together  by  fixed  articula- 
tions, while  in  the  cloven-footed  line  it  is  interrupted  by  the  hinge 
between  the  first  (astragalus)  and  second  rows  of  bones.  The 
hinge-joint,  being  more  liable  to  luxation  than  the  fixed  articula- 

*  "Journal  Academy  Philadelphia,"  March,  1874. 
f  "American  Naturalist,"  October,  ISY?. 


ORIGIN  OF  FOOT  STRUCTURES  OF  THE  UNGULATES.      369 

tion,  requires  a  wider  basis  of  support,  such  as  would  be  furnished 
by  two  divergent  digits,  rather  than  by  a  single  central  one. 

In  the  early  types,  w^here  the  median  digits  are  slender,  the 
mechanical  advantage  in  favor  of  the  bidigital  over  the  undigital 
arrangement  is  much  more  obvious  than  in  modern  genera.  Late 
in  time,  the  horse  developed  the  middle  digit  to  such  a  width  as 
to  form  almost  as  good  a  support  as  the  bidigital  structure.  In 
the  Eocene  genera,  the  slender  median  digit  could  not  have  sus- 
tained the  weight  on  a  hinge,  without  great  risk  of  dislocation. 


s 


Fig.  70. 


Fig.  71. 


Fig.  70. — Eight  posterior  foot  of  a  species  of  Corypliodon  from  New  Mexico,  one 
half  natural  size.     From  Report  Expl.  W.  of  100th  Mer.,  G.  M.  Wheeler,  iv,  PI.  ILx. 

Fig.  71. — Right  posterior  foot  of  the  rhinoceros,  ApJielops  megalodus  Cope,  from 
Colorado,  one  half  natural  size.  From  Report  U.  S.  Geol.  Surv.  Terrs.  F.  V.  Hayden, 
iv,  PI.  cxxx. 

This  explanation,  it  can  be  said,  applies  only  to  the  posterior  foot. 
The  posterior  foot  has,  however,  led  the  way  in  the  evolution  of 
Ungulata,  and  the  fore  foot  may  have  followed  in  accordance 
with  the  law  of  antero-posterior  symmetry  in  growth.  A  curi- 
ously malformed  deer  from  Mendocino  County,' Cal.,  throws  some 
light  on  this  subject.  It  has  apparently  a  single  functional  digit 
on  each  foot.  Examination  shows  that  the  posterior  foot  is  bi- 
digital, but  that  the  phalanges  are  fused  ;  while  the  anterior  foot 
24 


370 


MECHANICAL  EVOLUTION. 


is  perissodactyle,  all  the  digits  but  the  third  being  rudimental  ! 
Similar  evidence  is  furnished  by  the  genus  Anoplotlierium  *  of  the 
French  Eocene.  Its  posterior  foot  is  modified  artiodactyle,  while 
the  anterior  is  modified  perissodactyle.     We  may  assume  from 


Fig.  72.  Fig.  73. 

Fig.  72. — Right  posterior  foot  of  ProtoTiippug  sejunctus  Cope,  from  Colorado,  about 
one  half  natural  size.     From  Eeport  U.  S.  Geol.  Surv.  Terrs.     F.  V.  Hayden,  iv. 

Fig.  73. — Eight  posterior  foot  of  Foehrotherium  labiatum  Cope,  from  Colorado,  three 
fifths  natural  size.     From  Hajden's  Eeport,  iv,  PI.  cxv. 

these  facts,  that  the  posterior  foot  is  more  subject  to  the  influ- 
ences which  tend  to  produce  the  bidigital  structure  than  is  the 
anterior  limb. 

*  Euryiherium  Gerv.  in  the  original,  a  name  shown  by  Schlossev  to  apply  to 
Anoplotherium.     (Ed.  1886.) 


ORIGIN  OF  FOOT  STRUCTURES  OF  THE  UNGULATES.      37I 


I  suspect  that  the  production  of  a  ginglymus  in  the  middle  of 
the  tarsus  has  been  due  to  the  use  of  the  posterior  limb  in  soft 
swampy  ground.  In  the  absence  of  this  condition,  as  in  a  life  on 
harder  ground  than  swamp,  no  ginglymus  would  be  formed. 
The  action  of  an  ungulate  in  walking  through  deep  mud  is  very 
suggestive.  The  posterior  foot  is  bent  on  the  leg,  and  the  antero- 
posterior strain  of  the  weight  or  propulsive  force  is  transverse  to 
its  long  axis.  In  progression  on  dry  land,  the  impact  is  in  the 
direction  of  the  length  or  axis  of  the  foot.  The  obvious  effect  of 
a  cross  strain  is  to  produce  by  degrees  greater  and  greater  mobility 
of  some  articulation.  The  one  which  has  yielded  is  that  between 
the  two  tarsal  rows.  Another  effect  of  walking  in  swampy  ground 
is  to  spread  the  digits  apart.  As  the  first  digit 
of  both  feet  is  always  of  reduced  size,  there  are 
practically  but  four  digits  to  be  considered. 
The  weight  falling  nearly  medially  on  these, 
would  tend  to  spread  them  equally,  two  on 
each  side.  Thus  the  same  cause  may  have  been 
effective  in  producing  both  the  artiodactyle 
structures.  The  perissodactyle  structure,  so 
soon  as  the  lateral  digits  are  much  reduced, 
ceases  to  be  favorable  for  progression  in  soft 
ground,  owing  to  the  liability  of  the  lateral 
digits  to  injury,  in  following  the  principal  one 
into  the  yielding  material,  filled  with  sticks 
and  other  hard  debris. 

The  lowest  existing  forms  of  the  Artiodac- 
tyJa,  the  Omnivora,  are  universally  swamp 
lovers  and  livers.  So,  we  are  told,  are  the  lower 
existing  Perissodactyla,  the  tapirs  and  rhinoce- 
roses. The  higher  types  of  both  orders  are 
dwellers  on  plains  and  in  forests.  We  do  not 
know  the  habits  of  the  Eocene  Perissodactyla,  Colorado,  three  fifths 
but  I  doubt  their  having  inhabited  muddy  ^^a^urai  size.  From 
ground  to  the  same  extent  as  the  hogs  and  hip-  pf^^xT  ^  ^^^°  '  ^^' 
popotami,  the  lowest  of  the  Artlodadyla.  Now, 
in  progression  on  dry  land,  any  pre-existent  inequality  in  the 
length  of  the  digits  would  tend  to  become  exaggerated.  Such  an 
inequality  exists  in  the  Amllypoda,  the  third,  digit  being  a  little 
the  longer.  In  rapid  movement  on  hard  ground  the  longest  toe 
receives  the  greatest  part  of  the  impact,  even  if  its  excess  of 


Fig.  74.— Left  fore 
foot  with  part  of  ra- 
dius of  Poebrotheritim- 
mlso/ii    Leidy,    from 


372  MECHAmCAL  EVOLUTION". 

length  is  but  little.     The  harder  the  ground,  the  larger  the  pro- 
portion of  impact  it  will  receive. 

The  fact  that  the  Perissodadyla  did  not  develojo  the  solid  un- 
gulate or  equine  foot  until  a  late  geological  jDcriod,  or,  in  other 
words,  that  the  orders  so  long  retained  the  digital  formula  4 — 3, 
would  indicate  that  it  did  not  adopt  a  habitat  wdiich  required 
great  speed  as  a  condition  of  safety,  so  early  as  the  Artioclactyla. 


XVI. 

ON"    THE    EFFECT    OF    IMPACTS    AND    STRAINS    ON 
THE  FEET   OF  MAMMALIA.* 

The  principal  specializations  in  the  structure  of  the  feet  of  the 
Mammalia  may  be  summarized  as  follows  : 

I.  The  reduction  of  the  number  of  the  toes  to  one  in  the  Peris- 
sodadyla  (horses,  etc.),  and  two  in  the  Artiodactyla  (cloven  feet). 

II.  The  second  hinge-Joint  in  the  tarsus  of  the  Artiodactyla. 

III.  The  trochlear  ridges  and  keels  at  the  various  movable 
articulations  of  the  limbs.     These  are  as  follows  : 

1.  Looking  downward — 

a,  Intertrochlear  crests  of  the  humerus. 

/?.  On  the  carpal  end  of  the  radius. 

y.  Metacarpals,  distal  ends. 

6.  Tibia  distally. 

e.  Metatarsals  distally. 

2.  Looking  upward — 

a.  Radius  distally. 

j9.  Astragalus,  edges. 

y.  Astragalus  distally  {Artiodactyla). 

6.  Phalanges  (very  weak). 

The  following  observations  may  be  made  respecting  the  struct- 
ures included  under  Division  III :  The  trochlear  keels  which  look 
downward  are  much  the  most  prominent  and  important.  Those 
enumerated  as  looking  upward  are  weak  and  insignificant,  or  of  a 
different  character  from  the  down-looking  ones.  The  latter  are 
all  projections  from  the  middles  of  the  ends  of  the  respective  ele- 
ments. The  up-looking  are  generally  projections  of  the  edges  of 
bones.  Such  are  the  lateral  crests  of  the  astragalus,  and  the  ad- 
jacent edges  of  the  cuboid  and  navicular  bones  which  cause  the 
distal  emargination  of  the  astragalus  in  the  Artiodactyla.     The 

*  Read  before  the  National  Academy  of  Sciences,  April,  1881,  Abstract.  Some 
of  the  points  of  this  paper  have  already  been  discussed  in  the  preceding  article,  but 
the  present  abstract  contains  additional  matter. 


374  MECHANICAL  EVOLUTION. 

proximal  ridges  of  the  phalanges  are  very  weak,  and  the  concavities 
in  the  extremity  of  the  radius  can  not  be  called  trochlear,  as  they 
are  adaptations  to  the  carpal  bones. 

I.  The  reduction  in  the  number  of  toes  is  supposed  to  be  due 
to  the  elongation  of  those  which  slightly  exceeded  the  others  in 
length,  in  consequence  of  the  greater  number  of  strains  and  im- 
pacts received  by  them  in  rapid  progression,  and  the  complement- 
ary loss  of  material  available  for  the  growth  of  the  smaller  ones. 
This  is  rendered  probable  from  the  fact  that  the  types  with  re- 
duced digits  are  dwellers  on  dry  land  in  both  orders,  and  those 
that  have  more  numerous  digits  are  inhabitants  of  swamps  and 
mud.  In  geological  history  it  is  supposed  that  the  Perissodactyles 
(Figs.  72,  73)  originated  from  the  AmUypoda,  or  primitive  Ungu- 
lata  (Figs.  69,  70),  which  first  assumed  terrestrial  habits,  while 
the  Artiodadyla  (Fig.  74),  originating  from  the  same  order,  long 
continued  as  mud  dwellers  ;  as  witness  the  hippopotami  and  hogs 
of  to-day.  The  mechanical  effect  of  walking  in  the  mud  is 
to  spread  the  toes  equally  on  opposite  sides  of  the  middle  line. 
This  would  encourage  the  equal  development  of  the  digits  on  each 
side  of  the  middle  line,  as  in  the  cloven-footed  types.  In  progres- 
sion on  hard  ground,  the  longest  toe  (the  third)  will  receive  the 
greatest  amount  of  shock  from  contact  with  the  earth.  There  is 
every  reason  to  believe  that  shocks,  if  not  excessive,  encourage 
gi'owth  in  the  direction  of  the  force  applied.  This  is  strongly 
suggested  by  the  relations  between  the  length  of  the  legs  and  the 
rate  of  speed  of  animals  ;  and  the  lengths  of  the  teeth  and  their 
long-continued  use.  Certain  it  is  that  the  lengths  of  the  bones  of 
the  feet  of  the  Ungulate  orders  have  a  direct  relation  to  the  dry- 
ness of  the  ground  they  inhabit,  and  the  possibility  of  speed  which 
their  habitat  permits  them,  or  necessarily  imposes  on  them. 

II.  The  hinge  between  the  first  and  second  series  of  tarsal 
bones  in  the  Artiodadyla  may  be  accounted  for  by  reference  to 
the  habits  which  are  supposed  to  have  caused  the  cloven-footed 
character.  Observation  on  an  animal  of  this  order  walking  in 
mud,  shows  that  there  is  a  great  strain  antero-posteriorly  trans- 
verse to  the  long  axis  of  the  foot,  which  would  readily  cause  a 
gradual  loosening  of  an  articulation  like  that  connecting  the  two 
series  of  tarsals  in  the  extinct  Amblypoda.  Any  one  who  has  ex- 
amined this  part  of  Corypliodon  will  see  that  a  little  additional 
mobility  at  this  point  w^ould  soon  resemble  the  second  tarsal  joint 
of  the  hogs.      In   the  case  of  animals  which  progress  on  hard 


IMPACTS  AND  STRAINS  ON  TOE  FEET  OF  MAMMALIA.     375 


ground,  no  such  cross-strain  would  be  experienced,  and  the  effect 
would  be  to  consolidate  by  flattening  the  fixed  articulation. 

III.    The   trochleae.      These    prominences,   which    form  the 
tongues  of  the  tongue  and  groove  articulations,  exhibit  various 
degrees  of  development  in  the  different  Mammalia,      Those  of 
different  parts  of  the  skeleton  coincide  in  their 
condition  in  any  one  type  of  ambulatory  Mam- 
malia, and  so  may  be  all  considered  together. 
This   fact  suggests   strongly  that  they  are   all 
due  to  a  common  cause. 

They  are  all  imperfect  in  the  Rodentia  and 
Carnivora  (Figs.  75-77)  (except  the  Leporidce, 
which  are  especially  characterized  by  their  great 
speed).  Among  ungulates  they  are  very  imjDer- 
f  ect  in  the  Prohoscidea. 
The  orders  mentioned 
all  have  elastic  pads  on 
the  under  sides  of  their 
feet  or  toes.  The  same 
is  true  of  the  lowest 
types  of  both  the  Ar- 
tiodactyla  and  Perisso- 
dactyla,  the  hippopo- 
tami and  rhinoceroses. 
In  the  Rumina7itia  the 
trochleae  are  well  de- 
veloped (Fig.  80)  with 
one  exception,  and  that 
is  the  distal  metacar- 
pal and  metatarsal 
keels  of  the  Camelidm 
(Figs.  79,  81).  These 
animals  confirm  the 
probability  of  the  keels 
being  the  effect  of  long- 
continued  shocks,  for 
they  are  the  only  Euminants  which  have  elastic  pads  on  the  in- 
ferior sides  of  their  digits. 

That  these  processes  may  be  displacements  due  to  shocks  long 
continued,  is  rendered  probable  by  the  structure  of  the  bones 
themselves.     (1)  They  project  mostly  in  the  direction  of  gravity. 


Fig.  75.  Fig.  76.  Fio.  78.      Fig.  77. 

Fi^.  75,  Distal  extremity  of  tibia  of  Amhlyctonus 
sinosus   Cope.     Fig.   76,  Distal  extremity  of  tibia  of 
Oxycena  morsitans  Cope.    Both  flesh-eaters,  and  two 
thirds  natural  size.     From  Eeport  Expl.  and  Surv.  W. 
of  100th  Mer.,  G.  M.  Wheeler,  iv,  Pt.  ii. 

Fig.  77,  End  of  tibia  and  astragalus  of  Archcelurus 
debilis.  Fig.  78^  Femnr  of  jyimravusffomphodus.  Car- 
nivora ;  one  third  natural  size.     Mus.  Cope. 


376 


MECHAmCAL  EVOLUTION". 


Constant  jarring  on  the  lower  extremity  of  a  hollow  cylinder  with 
soft  (medullary)  contents  and  flexible  end  walls,  w^ould  tend  to  a 
decurvature  of  both  inferior  and  superior  adjacent  end  walls.     If 

the  side  walls  are  wide  and  resistant,  the 
projection  will  be  median,  and  will  be 
prolonged  in  the  direction  of  the  flexure 
of  the  joint.  The  groove  of  the  astraga- 
lus deepens  coincidently  with  the  increase 
of  digitigradism,  showing  that,  while  it 

is  primarily  pro- 
duced by  shocks, 
it  is  extended 
fore  and  aft  by 
the  repeated  flex- 
ure of  the  ankle- 
joint.     (2)  They 


Fig.  7U. 


Fig.  80. 


Fig.  81. 


Fig.  79,  Part  of  anterior  foot  of  Procamelus  occidentalis  from  New  Mexico.  Oiig- 
inal  from  Eeport  of  Capt.  G.  M.  Wheeler,  vol.  iv,  Pt.  ii. 

Fig.  80,  Metacar]~>als  of  Cosoryx  furcatus  from  Nebraska,  two  thirds  natural  size, 
c,  anterior  face  ;  ft,  posterior ;  c,  proximal  end ;  d^  distal  end. 

Fig.  81,  Left  fore  foot  with  part  of  radius  of  Poehrotherium  tilsoni  Leidy,  from 
Colorado,  tiiree  fifths  natural  size.     From  Hajden's  Eeport,  iv. 


fit  entering  grooves  of  the  proximal  ends  of  corresponding  bones. 
These  will  be  the  result  of  the  same  application  of  force  and 


IMPACTS  AND  STRAINS  OX  THE  FEET  OF  MAMMALIA.     377 

displacement  as  the  protrusion  of  tlie  inferior,  commencing  with 
a  concavity  (Eleplias) ;  becoming  more  concave  (Fig.  77),  and 
becoming  finally  a  groove.  (3)  When  the  dense  edge  of  a  bone, 
as  in  the  case  of  the  lateral  walls  of  the  astragalus,  is  presented 
upward,  a  groove  is  produced  in  the  down-looking  bone  ;  e.  g., 
the  lateral  grooves  of  the  distal  end  of  the  tibia.  (4)  When  the 
inferior  bones  are  the  denser,  the  superior  articular  face  yields ; 
e.  g.,  the  distal  end  of  the  radius  to  the  first  row  of  carpals 
(Fig.  81). 

(5)  The  metapodial  keels  commence  in  the  lower  types  on  the 
posterior  side  of  the  distal  extremity  of  the  bone.  This  is  j^artly 
due  to  the  presence  there  of  a  pair  of  sesamoid  bones  which,  with 
the  tendons  in  which  they  are  developed,  sustain  and  press  on  the 
lateral  parts  of  the  extremities,  and  leave  the  middle  line  without 
support  (Figs.  79-81). 


PART   IV. 

METAPHYSICAL    EYOLUTIOIsr. 


XVII. 

THE     EVOLUTIONARY     SIGNIFICANCE     OF    HUMAN 

CHARACTER.* 

The  complicated  constitution  of  the  human  mind  is  well  im- 
pressed on  the  investigator  as  he  seeks  to  understand  the  origin 
of  any  one  of  the  many  different  types  of  character  which  come 
before  him.  The  number  of  possible  combinations  of  its  numer- 
ous elements,  each  of  which  present  developmental  phases,  is 
necessarily  very  great.  The  species  of  human  minds,  as  one  may 
properly  term  them,  are  probably  as  numerous  as  the  species  of 
animals,  as  defined  by  their  physical  structure.  As  in  the  case 
of  anatomical  species,  however,  analysis  of  the  mind  reduces  its 
many  details  to  a  few  leading  departments.  Although  the  classi- 
fication of  the  elements  of  the  mind  is  a  classification  of  func- 
tions, it  is,  if  correct,  a  sure  index  of  the  classification  of  struct- 
ure also  ;  of  the  grosser  and  more  minute  structure  of  the  brain, 
principally  of  the  gray  matter. 

The  division  of  mental  activities  into  three  primary  divisions 
is  generally  admitted.  These  are  :  the  emotions,  the  intellect,  and 
the  will.  The  emotions  include  the  likes  and  dislikes,  or  the 
tastes,  and  their  strongest  forms,  the  emotions  and  the  passions. 
The  intellect  includes  those  powers  which  rearrange  the  experi- 
ences in  an  order  different  from  that  in  which  they  enter  the 
mind.  This  new  order  may  have  sole  reference  to  questions  of 
liking  and  disliking,  and  is  then  a  product  of  the  imagination  ; 

*  The  present  article  is  in  continuation  of  the  previous  one  on  the  Evolutionary 
Significance  of  Human  Physiognomy,  published  in  the  "Naturalist"  of  June,  1883. 


EVOLUTIONARY  SIGNIFICANCE  OF  HUMAN  CHARACTER.    379 

or  it  may  be  a  result  of  experience  of  the  laws  of  pure  necessity, 
without  regard  to  questions  of  taste  ;  then  it  is  a  process  of  rea- 
son. The  will,  properly  so  called,  is  the  spontaneous  power  of 
the  mind  by  which  the  other  processes  are  originated,  directed 
or  restrained.  The  range  of  the  will,  and  even  its  existence,  are 
questions  of  dispute. 

Below  and  behind  these  mental  activities  lies  seiisihility  or 
consciousness,  in  its  forms  of  general  and  special  sensation  ;  that 
is,  touch  and  hearing,  taste,  smell,  sight,  and  the  muscular  sense, 
with  many  others,  concomitants  of  both  health  and  disease.  It  is 
well  understood  that  these  primitive  mental  qualities  are  more  or 
less  developed  in  animals  in  which  the  more  purely  mental  func- 
tions are  rudimental.  The  doctrine  of  evolution  teaches  that 
from  this  class  the  higher  activities  of  the  mind  have  been  devel- 
oped, during  long  ages,  through  the  agency  of  memory.  The 
nature  of  the  present  essay  only  permits  a  casual  reference  to  the 
astonishing  character  of  memory,  and  the  remark  that  its  phe- 
nomena demonstrate  most  clearly,  of  all  others,  that  mind  is  an 
attribute  of  some  kind  of  matter. 

If  we  now  consider  these  natural  divisions  of  the  mind  as  they 
present  themselves  in  the  combinations  which  we  call  human 
character,  we  shall  observe  a  variety  in  the  mode  of  their  action 
which  pervades  all  divisions  alike.  These  variations  fall  under 
two  heads,  those  of  quantity  and  of  quality. 

Thus  as  to  quantity  ;  one  human  mind  may  present  a  greater 
amount  of  intellectual  than  emotional  activity  ;  of  imaginative 
than  rational  intellection  ;  of  affectionate  than  irascible  emotion  ; 
of  gastronomic  than  musical  taste,  etc.,  etc.  The  quantity  here 
indicated  is  probably  an  index  of  the  proportion  of  brain  tissue 
devoted  to  the  functions  mentioned.  The  intensity  or  force  of  the 
action  is  a  matter  of  quality. 

Of  qualities  the  variety  is  much  larger.  They  are  often  paral- 
lel to  those  of  inorganic  force,  and  suggest  the  same  kind  of  modi- 
fications of  the  material  bases  as  those  which  affect  the  latter. 
Two  prominent  qualities  are  fineness  and  coarseness.  Fineness 
observes  and  uses  detail  in  both  rational  and  emotive  acts,  and  is 
essential  to  the  precision  of  finish.  Coarseness  neglects  detail, 
but  deals  with  the  gross  of  things,  and  is  sometimes  accompanied 
by  largeness  of  quantity.  When  it  is  not,  the  result  is  not  good. 
Fineness  is,  on  the  other  hand,  often  associated  with  smallness.  It 
is  a  more  feminine  attribute,  while  coarseness  is  more  masculine. 


380  METAPHYSICAL  EVOLUTIOK 

Another  pair  of  antitlietic  qualities  are  intensity  of  action  and 
the  reverse.  This  probably  means  that  a  given  bulk  of  brain 
tissue  produces  (i.  e. ,  converts)  a  greater  amount  of  energy  in  a 
given  time  than  an  equal  bulk  of  non-intense  tissue. 

The  speed  or  rate  of  action  in  time,  and  its  opposite,  slowness, 
are  related  to  the  last-named  qualities,  but  are  not  identical  with 
them.  Thus  growth  of  the  mind  always  witnesses  a  diminution 
in  the  rate  of  action,  but  an  increase  in  intensity. 

Tenacity  of  mental  action  is  a  very  marked  character,  and  of 
great  importance.  It  signifies  the  persistence  of  mental  action, 
or  mental  endurance,  and  may  characterize  the  entire  mind,  or 
only  a  part  of  it.  Its  opposite,  seen  in  changeability,  desultori- 
ness  or  fickleness,  may  also  characterize  all  or  a  part  only  of  the 
mind.  According  as  it  characterizes  the  intellectual  or  emotional 
departments  are  its  exhibitions  most  varied,  though  they  probably 
have  a  common  histological  basis. 

Impressihility  and  stolidity  express  antitheses  of  character 
which  are  seen  every  day.  The  term  impressibility  is  used  as 
identical  with  irritability,  and  is  preferred,  because  the  latter  has 
special  physiological  and  popular  meanings,  some  of  which  are 
only  among  its  phases.  These  qualities  are  apt  to  pervade  the 
entire  mental  organism,  although,  like  others,  they  may  char- 
acterize a  part  only.  Impressibility  is  obviously  a  condition  of 
tissue,  since  it  varies  greatly  with  physiological  conditions  in  the 
same  person.  Its  exhibitions  in  the  department  of  the  emotions 
may  be  confounded  with  strong  development  of  the  emotions 
themselves.  A  moment's  thought,  however,  shows  that  easy  ex- 
citation of  emotion  is  a  different  thing  from  energy  of  emotion, 
and  is  often  found  apart  from  it.  Impressibility  of  intellect 
shares  with  tenacity  a  leading  position  as  an  attribute  of  a  first- 
class  mind,  and  the  combination  of  the  two  forms  a  partnership) 
of  superior  excellence. 

I  may  mention  here  a  quality  whose  absence  is  pathological, 
and  hence  does  not  properly  enter  the  field  ;  this  is  tonicity.  In 
its  normal  condition,  every  organ  should  be  supplied  with  suffi- 
cient nutriment  or  energy  to  insure  the  occupation  of  its  entire 
mechanism.  Anything  short  of  this  is  followed  by  poor  work. 
Debility  of  mental  action  in  the  emotional  department  is  seen  in 
abnormal  irritability,  such  as  peevishness  or  *^ spooning"  ;  and  in 
the  intelligence,  in  absence  of  mind  and  blundering;  and  in  both, 
in  general  frivolity. 


EYOLUTIOXARY  SIGNIFICANCE  OF  HUMAN  CHARACTER.    381 

Eeturning  to  the  primary  elements  of  mind,  we  may  examine 
their  divisions  with  reference  to  the  question  of  growth.  To  be- 
gin with  the  perceptions,  there  are  great  diversities  in  the  acute- 
ness  of  the  general  and  special  senses,  and  greater  and  less  sus- 
ceptibilities to  physical  pleasure  and  pain.  In  the  important 
representative  faculty,  memory,  the  ditferences  between  people 
are  great.  As  perception  as  well  as  thinking  involves  a  certain 
amount  of  structural  change,  it  is  evident  that  susceptibility  or 
impressibility  of  the  senses,  which  is  the  first  stage  of  memory, 
signifies  ready  metamorphosis  of  tissue.  Unimpressibility,  which 
impedes  memory,  is  a  consequence  of  resistance  on  the  part  of 
tissue  to  the  usual  stimuli.  Hence  the  effect  of  "  sights,  sounds, 
and  sensations  "  is  greatest  in  childhood,  and  the  memory  is  most 
impressible,  for  at  that  time  the  nervous  tissue  is  undergoing  con- 
stant change,  and  nutrition,  being  in  excess  of  waste,  constantly  \ 
presents  new  material  to  be  organized.  And  I  may  here  refer  to 
the  general  truth,  that  consciousness  of  all  kinds  is  the  especial 
and  distinguishing  attribute  of  life  as  distinguished  from  death 
or  no  life.*  Whatever  other  phenomena  we  may  be  accustomed 
to  regard  as  "vital,"  are  only  distinguishable  from  inorganic 
motion  or  force,  because  they  primitively  took  their  form  under 
the  guidance  of  consciousness,  and  are  hence,  so  to  speak,  its 
children.  With  the  perfect  working  of  most  of  the  mechanism  of 
the  body,  consciousness  no  longer  concerns  itself,  although  it  may 
speedily  do  so  in  pathological  conditions.  This  prerogative  is 
now  restricted  to  the  nervous  system,  and  to  certain  parts  of  it ; 
the  one  which  is,  histologically  speaking,  the  most  generalized  of 
the  systems.  And  it  is  quite  consistent  with  the  '^^  doctrine  of 
the  unspecialized,"  that  nervous  tissue  in  its  unfinished  state  in 
childhood  should  be  more  impressible  to  stimuli  than  at  later 
periods  of  life.  But  this  statement  requires  this  modification, 
that  there  is  a  stage  of  imperfection  of  mechanism  which  does  not 
display  high  sensibility,  as,  for  instance,  in  the  earliest  infancy. 
With  age  sensibility  gradually  diminishes. 

Next  in  order  of  appearance  in  growth  are  the  emotions.  It 
is  true  that  some  of  these  are  not  fully  developed  until  long  after 
the  appearance  of  many  or  all  of  the  intellectual  faculties  ;  but  it 
is  also  true  that  their  full  development  precedes  that  of  the  intel- 
lect, in  so  far  as  they  are  developed  at  all.     The  primitive  condi- 


*  "The  Origin  of  the  Will,"  "  Penn  Monthly,"  1877,  p.  440. 


382  METAPHYSICAL  EVOLUTION. 

tion  of  the  emotions  is  that  of  appetites.  The  first  of  these  in 
the  necessary  physiological  order,  and  hence  in  time,  is  the  appe- 
tite of  hunger.  Second  in  order  in  the  history  of  life,  but  not  in 
the  growth  of  individuals,  is  the  instinct  of  reproduction,  such  as 
it  is  in  animals  that  only  multiply  by  fission.  Very  early  in  evo- 
lution the  emotion  of  fear  must  have  arisen,  and  it  is  probably 
the  immediate  successor  of  hunger  in  the  young  of  most  animals. 
Anger  appears  as  early  as  the  mind  can  appreciate  resistance  to 
its  first  desires,  and  no  doubt  followed  as  third  or  fourth  in  the 
history  of  evolution.  The  rudiments  of  parental  feeling  would 
follow  the  origin  of  reproduction  at  a  considerable  interval  of 
time.  One  of  the  latest  of  the  instincts  to  appear  would  be  the 
love  of  power ;  while  later  still  would  be  the  emotions  of  rela- 
tivity (Bain),  because  they  are  dependent  on  a  degree  of  mental 
appreciation  of  objects.  Such  are  admiration,  surprise,  and  won- 
der. These,  as  well  as  all  other  consequences  of  inherited  intel- 
lect, appear  earlier  in  infancy  than  they  did  in  evolution,  as  may 
be  readily  understood. 

Of  these  instincts  and  emotions,  it  is  to  be  supposed  that  hun- 
ger remains  much  as  it  has  ever  been.  The  reproductive  instinct 
'  has,  on  the  other  hand,  undergone  the  greatest  modifications. 
Sex  instinct  could  not  have  existed  prior  to  the  origin  of  the 
male  sex,  which  must  be  regarded  in  evolution  as  a  derivative 
from  the  female.  Hence  it  is  probable  that  the  parental  instinct 
preceded  the  sexual  in  time.  These  two  instincts  being  the  only 
ones  which  involve  interest  in  individuals  other  than  self,  furnish 
the  sources  of  sympathy  in  all  its  benevolent  aspects.  Hence  it 
has  developed  in  man  into  the  powerful  passion  of  love  ;  into 
affection  and  charity  in  all  their  degrees  and  bearings.  Fear  be- 
ing, as  Bain  shows,  largely  dependent  on  weakness,  has  varied  in 
development  in  all  times,  but  must  be  most  pronounced  in  ani- 
mals of  high  sensibility,  other  things  being  equal.  Hence  its 
power  has,  on  the  whole,  increased  until  it  probably  reached  its 
extreme  in  the  monkeys  or  the  lowest  races  of  men.  Increasing 
intelligence  of  the  higher  order  diminishes  the  number  of  its 
occasions,  so  that  it  is  the  privilege  of  the  highest  types  of  men 
to  possess  but  little  of  it.  The  earliest  of  the  emotions  of  rela- 
tivity to  appear  in  time  has  probably  been  the  love  of  beauty  ; 
how  early  it  may  have  appeared  it  is  difficult  to  imagine.  Sur- 
prise and  wonder,  as  distinct  from  fear,  one  can  only  conceive  as 
following  an  advanced  state  of  intelligence. 


EVOLUTIONARY  SIGNIFICANCE  OF  HUMAN  CHARACTER.   383 

Thus  in  psychology  as  in  physiognomy,*  the  palcontological 
order  of  development  is  somewhat  different  from  the  embryologi- 
cal.     I  might  compare  the  two  orders  as  follows  : 


PAL  EONTOLOGIC  AL. 

EMDRYOLOGICAL. 

Hunger. 

Hunger. 

Reproduction. 

Fear. 

Fear. 

Anger. 

Anger. 

Beauty. 

Parental  instinct. 

Wonder. 

Sex. 

Power. 

Power. 

Admiration. 

Beauty. 

Pity. 

Wonder. 

Sex. 

Parental  instinct. 

The  qualities  enumerated  in  the  first  column  follow  each  other 
directly  in  order  from  the  simple  to  the  complex.  In  the  second 
column  this  order  is  disturbed  by  the  earlier  appearance  of  the 
derivative  emotions,  beauty,  wonder,  admiration,  and  pity,  or  be- 
nevolence, and  the  later  appearance  of  the  simple  emotion  of  sex. 
Thus  in  psychological  as  in  other  evolution,  some  of  the  products 
of  development  appear  earlier  and  earlier  in  life  in  accordance 
with  the  law  of  acceleration. 

The  intelligence  has  already  been  considered  under  the  two 
heads  of  the  imagination  and  the  reason.  The  action  of  the  im- 
agination, unmixed  with  the  exercise  of  reason,  is  chiefly  to  be 
seen  in  the  creative  fine  arts,  as  distinguished  from  the  imitative, 
the  mechanic,  and  other  arts.  The  musician,  the  painter,  the 
sculptor,  the  poet,  the  novelist  and  the  playwright,  so  far  as  they 
are  not  imitators,  present  the  best  illustrations  of  the  work  of  the 
imagination.  It  is  a  faculty  which  must  be  very  little  developed 
in  the  animals  below  man.  They  occasionally  make  mistakes  in 
the  nature  of  objects,  and  suppose  them  to  be  other  than  what 
they  are.  Thus  the  Antilocapra  supposes  the  Indian  disguised 
with  a  skin  and  horns  to  be  one  of  his  own  species,  and  suffers 
the  penalty.  But  this  is  a  most  rudimental  act  of  imagination,  if 
it  be  not  mere  curiosity. 

The  reason,  properly  so  called,  begins  in  its  lowest  grades  with 
the  simplest  re-arrangement  of  the  objects  of  sense  and  memory, 
in  accordance  with  some  principle  of  relation.  As  the  principle 
or  standard  of  relation  varies,  so  does  the  intellectual  process.     If 


*"  Naturalist,"  1883,  p.  618. 


384  METAPHYSICAL  EYOLUTION". 

the  process  be  discovery,  or  the  enlargement  of  knowledge,  many 
experiences  (or  hypotheses)  will  be  successiyely  encountered  and 
tested,  and  appropriate  generalizations  reached  (inductions).  If 
the  process  be  to  accomplish  the  practical  ends  of  life  by  use  of 
well-known  means,  the  intellect  uses  the  customary  rules  of  action 
as  standards,  be  they  moral  or  mechanical,  financial  or  political, 
and  attains  its  deductions  and  applications.  These  two  types  of 
intellect  are  strikingly  distinct,  and  produce  the  most  diverse  con- 
sequences. The  inductive  type  is  the  most  generalized,  and  hence 
callable  of  the  largest  growth  and  adaptability,  and  the  widest 
range  of  thought.  The  deductive  is  the  more  specialized,  the 
more  ^^  practical,"  but  less  capable  of  growth  or  general  thought. 
Its  most  remarkable  exhibitions  are  seen  in  the  skill  with  which 
some  men  conduct  the  game  of  chess,  and  corresponding  enter- 
prises in  real  life.  Also  the  ingenuity  of  mechanical  invention, 
and  the  wonderful  rapidity  of  calculation  which  some  minds  dis- 
play. In  intellectual  as  in  many  other  vital  phenomena,  the  facil- 
ity once  developed,  the  active  process  is  often  unaccompanied  by 
consciousness  in  many  or  even  all  of  its  stages. 

Rapid  and  exact  control  of  the  muscles  in  obeying  the  direc- 
tions of  the  mind  is  essential  to  the  practice  of  many  arts,  espe- 
cially to  that  of  the  musician.  This  accomplishment  is  acquired 
through  the  medium  of  the  conscious  mind,  and  may  be  regarded 
simply  as  the  reflex  of  impressions  made  on  the  senses  directed  by 
some  simple  rule  which  has  been  impressed  on  the  memory.  The 
often  surprising  results  involve  the  exercise  of  a  very  simj^le  phase 
of  intellection. 

The  appearance  of  the  rational  faculties  in  time,  may  be  esti- 
mated by  their  relative  development  in  the  existing  divisions  of 
animals  whose  period  of  origin  is  known  or  inferred.  The  ani- 
mal mind  is  capable  of  simple  forms  of  induction  and  deduction, 
and  sometimes  acquires  considerable  artistic  skill.  Bees,  ants  and 
spiders  display  these  in  varying  degrees,  and  their  antiquity  is 
probably  co-extensive  with  that  of  the  known  sedimentary  rocks. 
The  supposed  Ascidian  ancestors  of  the  Vertebrata,  and  even  the 
lowest  vertebrate  (Branchiostoma),  display  far  less  intelligence  than 
the  articulates  mentioned,  which  are  really  lower  in  the  scale  of 
organic  types.  From  such  unpromising  sources  did  the  noble  verte- 
brate line  descend.  It  is  probable  that  the  inductive  act  preceded 
by  a  little  the  deductive  in  time,  as  it  does  in  logical  order.  But 
the  elaboration  of  these  powers  was  doubtless  long  delayed  ;  for 


EVOLUTIONARY  SIGNIFICANCE  OF  HUMAN  CIIxVRACTER.   385 

untold  ages  they  involved  nothing  more  than  the  discovery  and 
application  of  general  principles  of  the  simplest  kind  ;  such  as  the 
customary  sequence  of  natural  phenomena,  and  the  anticipation 
of  their  operations,  as,  for  instance,  in  the  laying  up  of  winter 
provisions.  Occasionally  deductive  application  of  an  old  rule  to  a 
new  case  would  arise,  as  in  that  of  the  Mygale  spider  which  was 
observed  by  Dr.  McCook  to  substitute  cotton  for  her  own  silk  for 
the  lining  of  her  nest.  The  development  of  the  rational  faculty 
has  been  rather  in  quantity  and  quality,  than  in  the  nature  of  its 
constituent  parts.  I  may  remark,  however,  that  the  embryological 
order  is  here  again  different  from  the  paleontological.  Inherited 
aptitudes,  as  for  music,  calculation,  etc.,  precede,  in  children,  any 
considerable  powers  of  thought,  while  the  order  of  development  of 
the  race  has  been  the  reverse. 

As  regards  the  appearance  of  the  qualities  of  mind  already 
mentioned,  which  depend  on  character  of  tissue,  it  is  difficult  to 
present  an  order  which  shall  be  generally  true.  Our  ignorance 
of  the  subject  is  profound ;  nevertheless  observation  of  animals 
and  men  leads  to  the  following  conclusions  :  First,  the  primitive 
mind  is  negative,  unimpressible,  and  little  sensitive.  In  evolution, 
sensibility  has  been  developed  under  stimuli,  and  diminished  by 
disuse  and  repose.  The  energy  of  high-strung  sensibility  has  prob- 
ably ever  won  for  its  possessors  success  in  the  struggle  for  existence, 
and  more  or  less  immunity  from  the  pains  which  stimulate  to  ac 
tion.*  It  is  true  that  the  non-aggressive  and  ever-harassed  Her- 
bivora  have  developed  the  higher  brain  structure.  The  inferiority 
of  brain  type  of  the  Carnivora  is  a  well-known  fact  of  present  and 
past  time.  The  early  ruminants  were  smaller  than  the  contempo- 
rary flesh-eaters,  and  therefore  subject  to  the  greatest  risks.  The 
best-developed  brains,  those  of  the  Quadrumana,  have  been  devel- 
oped in  still  more  defenseless  animals,  who  in  their  arboreal  life 
have  been  confronted  by  still  more  complex  conditions.! 

Impressibility  or  sensitiveness  has  evidently  been  the  means  of 
acquisition  of  some  of  the  other  qualities  mentioned.  Thus  inten- 
sity may  have  resulted  from  active  use  accompanied  by  vigorous 
nutrition,  and  the  consequent  construction  of  compact  force-con- 
verting tissue.     Rapidity  without  intensity  must  also  result  from 

*  "  The  Relation  of  Man  to  the  Tertiary  Mammalia,"  "Penn  Monthly,"  1875. 

f  Mr.  C.  Morris  very  reasonably  regards  the  social  life  of  these  animals  as  the 

source  of  their  development  of  intelligence.     See  "American  Naturalist,"  June, 

1886.     (Ed.  1886.) 
25 


386  METAPHYSICAL  EVOLUTION. 

exercise,  with  a  less  yigorous  construction  of  tissue.  Fineness  and 
tenacity,  on  the  other  hand,  can  not  be  regarded  as  being  so  much 
produced  by  use  as  by  very  primitive  conditions  of  tissue.  Ee- 
straint  under  ]3ressure  might  produce  fineness.  Long-continued 
freedom  from  sudden  changes,  under  pressure,  might  account  for 
the  origin  of  tenacious  tissue.  As  to  quantity,  deficiency  or  diver- 
sion of  nutritive  energy  or  material  must  produce  smallness,  and 
the  reverse  condition,  largeness. 

These  qualities  impress  themselves  on  the  external  as  well  as 
the  internal  organization,  and  can  be  more  or  less  successfully  dis- 
cerned by  the  observer.  I  reserve  the  question  of  physiognomy  to 
a  later  article,  and  here  consider  only  the  evolutionary  bearings  of 
character  itself.  As  in  physiognomy,  we  may  arrange  the  facul- 
ties and  their  qualities  under  the  two  heads  of  ancestral  and  embry- 
onic, or  that  of  the  species  and  that  of  the  individual.  The  order 
of  succession  is  the  same  in  both  kinds  of  development. 

SPECIES.  INDIVIDUAL. 

Indifference.  .  Indifference. 

Einotions.  Emotions. 

Intellect.  Intellect. 

a.  Imagination.  a.  Imagination. 

b.  Reason.  b.  Beaso7i. 

It  is  not  practicable  to  go  farther  than  this  into  the  order  of 
evolution  of  characteristics.  There  is  probably  little  uniformity 
of  sequence  other  than  that  I  have  already  pointed  out  under  the 
head  of  the  emotions. 

As  a  complex  outcome  of  the  emotional  and  rational  faculties 
must  be  now  mentioned  the  moral  sense,  or  the  sense  of  justice. 
It  consists  of  two  elements,  the  emotion  henevolence,  and  the  ra- 
tional power  of  discrimination  or  judgment.  The  former  fur- 
nishes the  desire  to  do  what  is  right  to  a  fellow-being.  Without 
the  aid  of  reason,  it  is  benevolence,  not  justice,  and  may  often  fail 
of  its  object.  The  rational  element  has  acquired  from  experience 
a  generalization,  the  law  of  right.  It  perceives  what  is  most  con- 
ducive to  the  best  interest  of  the  object  of  benevolence  in  his  rela- 
tion to  others  or  to  society,  or  whether  he  be  a  proper  object  of 
benevolence  at  all.  By  itself,  this  quality  is  absolutely  useless  to 
mankind.  When  it  guides  the  action  of  human  symj^athy,  it  dis- 
plays itself  as  the  most  noble  of  human  attributes.  Many  animals 
display  sympathy  and  benevolence,  but  justice  has  not  yet  been 
observed  in  anv  of  them.     Hence  it  has  been  said  that  it  can  not 


EVOLUTIONARY  SIGNIFICANCE  OF  HUMAN  CHARACTER.   387 

be  a  derivative  faculty,  but  is  '^intuitive"  in  man.  The  objec- 
tion to  this  view  is  its  great  variability  and  occasional  entire  ab- 
sence in  man,  individually  and  racially.  It  is  the  last  to  appear 
in  individual  growth,  as  it  has  doubtless  been  in  the  order  of  evo- 
lution, of  mind. 

I  now  devote  a  little  space  to  the  discussion  of  the  distribution 
of  these  qualities  in  races  and  sexes. 

As  regards  the  relative  preponderance  in  action  of  the  emotive 
and  intellectual  faculties,  it  is  an  axiom  that  in  the  great  majority 
of  mankind,  apart  from  the  necessities  imposed  by  the  simple 
physical  instincts,  it  is  a  taste  or  an  affection  or  an  emotion  that 
lies  at  the  basis  of  their  activities.  Perhaps  the  most  universal  is 
the  affection  of  sex.  Given  two  types  of  rational  beings  who  are 
objects  of  admiration  and  of  pleasure  to  each  other,  each  of  whom 
desires  to  possess  the  other,  and  who  therefore  employs  many  de- 
vices to  please  and  attract  the  other,  and  we  have  an  effective  agent 
of  general  development.  Then  the  parental,  and  especially  the 
maternal,  affections  arouse  and  direct  many  labors.  Fear  of  suf- 
fering and  death  is  at  the  basis  of  many  others.  The  love  of  power 
or  of  possession,  including  ambition,  is  a  well-known  stimulus. 
The  love  of  beauty  is  a  strong  motive  in  many  persons.  The 
pleasure  derived  from  the  exercise  of  the  intelligence  is  a  sufficient 
motive  for  a  life-work  in  a  comparatively  small  number  of  persons. 
These  are  the  artists  and  the  scientists  ;  but  it  is  far  from  being  an 
unmixed  motive  in  many  of  them. 

Intellectual  motives,  however,  enter  into  association  with  the 
affectional  in  many  instances,  as,  for  example,  in  the  profession  of 
teaching.  But  it  is  as  guide  and  agent  in  the  accomplishment  of 
the  main  ends  of  life  that  the  intellect,  especially  the  reason,  has 
its  great  field,  and  displays  itself  in  an  endless  variety  of  ways. 

If  we  now  survey  men  as  we  find  them,  it  is  a  general  truth 
that  it  is  in  the  male  sex  that  the  greatest  proportion  of  rational 
method  is  to  be  found,  and  in  the  female  the  greatest  proportion 
of  the  affectional  and  emotional.  As  we  descend  the  scale  of 
humanity,  the  energy  and  amount  of  the  rational  element  grows 
less  and  less,  while  the  affectional  elements  change  their  propor- 
tions. The  benevolent  and  sex  elements  diminish  in  force  more 
rapidly  than  the  other  sentiments,  but  it  is  probable  that  all  the 
emotions  are  less  active  in  savages,  excepting  those  of  power  and 
of  fear.  In  the  lowest  races  there  is  a  general  deficiency  of  the 
emotional  qualities,  excepting  fear,  a  condition  which  resembles 


388  METAPHYSICAL  EVOLUTION. 

one  of  the  stages  of  childhood  of  the  most  perfect  humanity.  To 
this  must  be  added  revenge,  where  hatred  may  be  re-enforced  by 
several  other  sentiments,  with  a  feeble  perception  of  equivalent 
suffering  or  punishment,  which  may  or  may  not  be  just.  The 
pleasure  of  muscular  exercise  is  greatly  developed  in  people  of  out- 
door habits. 

The  order  of  the  appearance  of  the  intelligence  is  nearly  de- 
pendent on  the  development  of  the  powers  of  observation.  In 
most  savages  these  are  very  acute,  and  vary  according  to  the  na- 
ture of  the  environment  which  impresses  them.  The  character 
of  most  civilizations  tends  to  diminish  the  power  of  the  ]3ercep- 
tive,  while  the  higher  departments  of  imagination  and  reason  are 
enlarged.  The  imagination  reached  a  high  development  before 
reason  had  attained  much  strength.  With  the  exception  of  a  few 
families,  the  intelligence  of  mankind  has,  up  to  within  two  or 
three  centuries,  expressed  itself  in  works  of  the  imagination. 
When  exact  knowledge  first  began  to  be  cultivated,  it  was  in  the 
department  of  astronomy,  where  the  least  precision  was  attain- 
able, and  where  the  greatest  scope  for  the  imagination  is  to  be 
found.*  Next  in  time  metaphysics  was  the  throne  of  learning,  a 
field  in  which  much  may  be  said  with  the  least  possible  reference 
to  the  facts  of  observation.  With  the  modern  cultivation  of  the 
natural  and  physical  sciences,  the  perceptive  faculties  will  be 
restored,  it  is  to  be  hojoed,  to  their  true  place,  and  thus  many 
avenues  opened  up  for  the  higher  thought-power  of  a  developed 
race.  Thus  it  is  that  in  the  order  of  human  development  there 
is  to  be  a  return  to  the  primitive  powers  of  observation,  without 
loss  of  the  later  acquired  and  more  noble  capacities  of  the  intellect. 

The  relation  of  the  qualities  of  impressibility,  fineness,  inten- 
sity, speed  and  tenacity,  to  our  development  in  time,  may  have 
been  as  follows  :  Impressibility  of  mind  is  no  doubt  an  embryonic 
character  of  ^'  retardation,"  parallel  to,  and  probably  a  consequence 
of,  the  retardation  which  is  also  expressed  in  the  human  skull  and 
face.  The  preponderance  of  the  osseous  and  nutritive  elements 
over  the  nervous  is  the  usual  accompaniment  of  non-impressi- 
bility, and  vice  versa.     Hence  this  quality  is  of  late  origin  in  the 

*  The  governments  of  antiquity  required  the  knowledge  of  the  Chaldean  astrono- 
mers as  important  to  the  success  of  their  undertakings,  and  the  governments  of 
Europe  and  America  were,  for  a  long  period,  more  liberal  in  their  support  of  as- 
tronomy than  any  other  science.  At  present,  however,  geology  shares  in  this  aid, 
and  to  a  less  degree  botany  and  zoology. 


EVOLUTION"ARY  SIGNIFICANCE  OF  HUMAN  CHARACTER.   389 

history  of  the  Vertebrata  and  of  man,  and  is  most  developed  in 
the  young,  and  better  developed  in  women  than  in  men. 

Tenacity  has  an  opposite  significance,  being  an  especial  charac- 
teristic of  maturity  in  the  human  mind.  Hence  it  may  have  been 
more  general  in  early  ages  than  at  present,  but  could  have  little 
value  so  long  as  the  mind  remained  small  in  quantity.  Curiously, 
it  is  a  quality  which  may  co-exist  with  a  good  deal  of  impressibility. 

Fineness  can  only  be  a  quality  of  full  development,  and  is 
totally  independent  of  the  other  qualities.  It  is  unknown  among 
savages,  and  is  developed  apj)arently  in  a  few  animals.  Of  inten- 
sity it  is  difficult  to  say  much  definitely.  The  nervous  operations 
of  animals  often  display  the  highest  degree  of  this  quality,  and  it 
is  not  unlikely  that  its  appearances  differ  as  much  in  savages  as 
in  civilized  people.  Its  importance  in  mental  action  depends  of 
course  on  the  kind  and  amount  of  mental  function  which  exhibits 
it.  The  same  may  be  said  of  speed.  The  faculties  which  exist 
are  more  or  less  affected  by  it.  In  the  well -formed  reason  it  is  an 
important  characteristic,  and  a  special  form  of  development. 

Having  gone  as  far  into  the  origin  and  developmental  relation 
of  mental  functions  and  qualities  as  the  nature  of  this  sketch  jier- 
mits,  I  refer  briefly  to  the  stimulus  to  their  growth  ;  always  re- 
membering that  the  percentage  of  inherited  qualities  is  much 
larger  in  a  given  character  than  that  of  acquired  ones.  On  this 
head  one  word  expresses  a  good  deal,  and  that  word  is  use.  No 
truth  is  better  known  than  this  one,  that  mental  faculties  develop 
with  use  more  rapidly  than  those  of  any  other  organ  of  the  human 
body.  Brain  and  nerve  are  apparently  the  most  plastic  of  all  tis- 
sues ;  the  one  which  retains  the  properties  of  the  primitive  pro- 
toplasm, multiplied  and  intensified  a  thousand  fold.  It  has  al- 
ways been  the  seat  of  creation,  throwing  off  its  "  formed  matter  " 
in  useful  directions.  It  is  still  doing  so  ;  and  in  the  human 
brain,  ever  creating  itself,  is  in  addition  the  seat  of  a  new  creation, 
which  it  executes  through  its  instruments,  the  other  organs  of 
the  body.  Hence  the  greatest  sin  against  the  brain  is  idleness, 
or  disuse.  The  brain  activity  of  to-day  is  an  indication  of  health 
and  happiness  beyond  what  the  world  has  seen  hitherto. 

The  greatest  stimulus  to  exercise  of  the  brain  is  human  soci- 
ety. Hence  the  greatest  developments  of  mind  have  always  been 
in  the  centers  of  population.  Whatever  may  be  the  passive  vir- 
tues of  country  life,  it  is  the  cities  that  furnish  both  the  stimulus 
and  the  field  for  the  triumphs  of  mind. 


y 


XVIIL 
CONSCIOUSNESS  IN   EVOLUTION.* 

I.    PRELIMIKAKY. 

The  evidence  of  what  is  termed  ^^  design  "  in  the  structure  of 
beings  exhibiting  life,  is  often  appealed  to  by  one  class  of  think- 
ers, as  proving  the  intervention  of  a  personal  Deity  in  the  crea- 
tion of  such  ;  and  the  same  feature  exhibited  in  the  movements 
of  living  creatures  is  regarded  by  metaphysicians  of  a  similar  class 
as  an  indication  of  their  possession  of  a  power  of  choice,  or  "  free 
agency,"  at  least  in  the  case  of  man.  The  opposing  school,  of 
whom  Professor  Bain  may  be  selected  as  an  example,  believes  that 
designed  acts  are  without  an  element  of  freedom,  but  are  simply 
performed  in  obedience  to  stimuli  of  various  kinds,  motion  fol- 
lowing stimulus  as  inevitably  as  effect  succeeds  cause  in  the  non- 
living world.  The  evolutionists  attempt  to  explain  design  in 
structure  through  the  operation  of  the  Darwinian  law  of  the 
*^  survival  of  the  fittest,"  showing  that  only  those  beings  whose 
organization  displays  that  adaptation  to  use  in  relation  to  its  sur- 
roundings, which  is  termed  '^design,"  could  possibly  continue  to 
exist.  It  is  justly  urged  against  this  reasoning  that  it  attempts 
no  explanation  of  the  origin  of  such  structures.  Another  school 
of  evolutionists  have  therefore  maintained  that  such  structures  are 
due  to  the  effect  of  effort,  i.  e.,  stimulus  or  use,  exerted  by  the 
living  being  on  its  own  body,  and  that  the  design  thus  displayed 
is  an  expression  of  the  intelligence  at  some  time  possessed  by  itself. 

So  long  as  there  is  any  probability  of  the  last  explanation 
proving  valid,  it  will  be  important  to  examine  into  the  questions 
of  metaphysics  which  it  necessarily  involves.  The  investigation 
is  indeed  but  the  necessary  projection  of  those  which  have  re- 
sulted in  satisfying  the  great  majority  of  biologists  of  the  reality 
of  evolution,  or  of  the  fact  of  the  descent  of  existing  living  beings, 

*  A  lecture  delivered  before  the  Franklin  Institute,  Philadelphia,  February,  1874. 


CONSCIOUSNESS   IN"  EVOLUTION.  391 

species  by  species,  order  by  order,  and  class  by  class,  from  others 
which  have  preceded  them  in  time.  Clearly,  then,  we  enter  the 
question  by  considering  the  nature  of  movements  of  plants  and 
animals  in  relation  to  the  stimuli  which  are  supposed  to  call 
them  forth. 

II.    THE   UNCONSCIOUS. 

A  true  study  of  metaphysics  necessarily  has  for  its  objects 
plants,  animals,  idiots,  and  infants,  as  well  as  healthy  men  ;  never- 
theless, necessity  compels  us,  in  discussing  the  question,  to  dwell 
on  our  own  experiences  as  a  sine  qua  non.  Now  experience,  in  a 
general  sense,  includes  not  only  the  memory  of  our  conscious  acts, 
but  a  knowledge  of  our  unconscious  ones,  and  to  the  latter  espe- 
cial attention  must  be  directed,  since  they  are  most  readily  over- 
looked. The  marvelous  character  of  memory  can  not  be  too 
much  considered.  Of  the  millions  of  impressions  which  the  mind 
has  received  and  registered,  in  the  course  of  a  lifetime,  but  one 
can  be  clearly  present  in  consciousness  at  one  time.  The  remain- 
ing millions  are  not  lost  ;  they  are  stored,  each  in  its  apj^ropriate 
place,  to  be  sprung  into  consciousness  when  the  apj)ropriate 
suggestion  presents.  How  much  more  vast,  from  this  point  of 
view,  is  the  unconscious  mind  than  the  conscious  !  But  the 
phenomenon  is  not  confined  to  memory.  Who  that  has  ever  at- 
tempted the  digestion  of  a  subject  which  includes  a  mass  of  de- 
tails, is  not  acquainted  with  the  unconscious  activity  of  the  mind 
in  classification  ?  How  frequently  a  question  involving  many 
parts,  is,  on  the  first  reception  of  the  constituent  facts,  all  con- 
fusion ;  but  in  time  displays  its  symmetry  clearly  to  the  con- 
sciousness, every  part  in  its  proper  place,  and  that  with  little  or 
no  further  attention  having  been  devoted  to  it.  It  is  indeed  proba- 
ble that  the  every-day  process  of  inductive  reasoning  is  conducted 
in  unconsciousness  on  the  part  of  the  subject.  Induction  con- 
sists in  the  generalization  of  some  quality  as  common  to  a  great 
number  of  objects  of  memory ;  a  greater  or  smaller  number  of 
other  qualities  being  neglected  in  the  process.  When  this  act  is 
performed  voluntarily,  one  or  many  qualities  are  successively 
passed  in  review  before  the  mind — each  one  being  in  its  turn  im- 
pressed on  the  perceptive  centers — so  long  as  it  is  the  object  of 
inquiry,  the  others  being  excluded  from  consciousness  for  the 
time  being.  It  is  simply  a  process  of  classification,  and  when  per- 
formed in  consciousness,  constitutes  "experiment."     But  when 


392  METAPHYSICAL  EVOLUTION". 

no  generality  is  anticipated,  and  its  existence  is  unknown,  it  often 
hajjpens  that  sucli  generalization  becomes  known  or  rises  into  con- 
sciousness, without  the  bestowal  of  effort  in  classification  of  the 
objects  to  which  it  refers.  The  impressions  consciously  received 
have  been  arranged  out  of  consciousness,  and  when  revived  into 
consciousness  display  an  order  wliich  was  not  previously  known 
to  exist.  It  is  in  the  latter  way  that  the  '^23ractical  man  "  "finds 
out "  the  rules  by  which,  as  by  an  instinct,  he  regulates  his  inter- 
course with  the  world.  He  often  can  not  explain  the  reasons  of 
their  truth,  nor  does  he  know  how  he  came  by  them,  being  gen- 
erally content  to  call  them  the  results  of  ^'  experience."  In  some 
persons  they  are  so  feebly  expressed  in  consciousness  as  to  be  called 
*' feelings"  ;  and  many  experiences  or  repetitions  are  sometimes 
necessary  to  impress  on  us  the  importance  of  these  mental  prod- 
ucts before  we  are  willing  to  follow  them  in  action.  '^  Strength 
of  mind  "  is  an  expression  applied  to  a  high  degree  of  this  uncon- 
scious reasoning  ;  expressing  the  extent  of  ground  the  process 
covers  continuously,  as  well  as  the  exactitude  of  its  results.  The 
experimental  investigator,  on  the  other  hand,  performs  this  work 
deliberately,  and  is  acquainted  with  the  processes  ;  he  is,  there- 
fore, at  first  more  confident  of  his  results.  And  we  observe  here, 
in  passing,  that  a  rule  once  discovered  is  as  readily  retained  in 
the  cells  of  the  unconscious  as  is  the  memory  of  a  simple  object 
or  event. 

Another  form  of  unconscious  cerebration  is  seen  in  deductive 
reasoning,  which  employs  rules  already  discovered  in  application 
to  new  cases.  Calculating  prodigies  are  a  case  in  point.  It  is 
well  known  that  those  persons  who  have  from  time  to  time  ap- 
peared possessed  of  the  power  of  calculating  with  enormous  num- 
bers with  marvelous  rapidity,  have  never  been  able  to  explain  the 
process  by  which  they  reach  their  conclusion,  nor  are  they  con- 
scious of  going  through  the  steps  involved  in  the  calculation  they 
perform  ;  and  it  has  been  said  that  great  calculators  have  rarely 
been  great  mathematicians. 

The  explanation  of  these  phenomena  is  not  far  to  seek.  In 
simpler  forms  it  is  presented  to  us  every  day.  Thus  it  is  an  easy 
matter  to  read  with  but  little  consciousness  of  the  process,  and  no 
recollection  of  the  subject-matter  of  what  is  read.  Most  manual 
operations  can  be  performed  while  the  consciousness  is  occupied 
with  other  objects. 

If  these  be  facts  of  human  experience,  how  much  more  likely 


CONSCIOUSNESS  IN  EVOLUTION.  393 

are  they  to  be  true  of  animals  ?  If  man  be  unconscious  of  the 
process  during  the  performance  of  some  of  his  most  complex  acts, 
how  much  more  probable  is  it  that  animals  are  so  while  pursuing 
the  narrower  circle  of  their  simpler  ones  ?  Yet  animals  are  not 
devoid  of  consciousness ;  indeed,  it  is  scarcely  credible  that  any 
one  should  deny  to  them  consciousness,  after  exjoerience  in  their 
education. 

But  let  these  automatic  acts  be  ever  so  simple  or  complex,  it  is 
here  claimed  that  they  could  not  have  origmated  out  of  conscious- 
ness. Whatever  we  call  voluntary  acts  in  ourselves  undoubtedly 
have  to  be  learned.  The  acquisition  of  the  primary  act  of  walking 
is  accomplished  by  a  slow  and  painful  education  ;  while  knitting 
and  other  manual  exercises  necessarily  require  preliminary  train- 
ing, some  of  shorter,  others  of  longer,  duration.  This  is  true  of 
such  voluntary  acts  as  we  perform  most  readily  automaticall}^,  and 
such  as  might  be  supposed  to  be  most  probably  acquired  by  heredi- 
tary transmission,  as  for  instance  speaking.  The  case  is  the  same 
with  animals.  All  those  services  which  are  useful  to  us,  or  tricks 
which  amuse  us,  are  acquired  at  the  expense  of  training,  which 
involves  a  system  of  stimuli,  consisting  of  rewards  and  punish- 
ments, as  in  our  own  species.  Is  there  any  reason  to  suppose  that 
those  habits  which  we  observe  them  to  possess  in  a  state  of  nature 
have  had  a  different  origin  ? 

It  is  incontrovertible  that  a  regular  succession  of  muscular 
movements  may  be  committed  to  memory  as  certainly  as  a  color 
or  a  shape,  and  that  a  change  of  brain  substance,  such  as  causes 
the  retention  of  the  simple  impression,  is  also  involved  in  the 
retention  of  the  complex.  When  this  machinery  is  completed, 
through  the  repetition  of  conscious  stimulus,  it  works  thenceforth 
without  necessary  intervention  of  consciousness.  The  conscious- 
ness may  then  be  engaged  in  fresh  acquisitions,  accomplishing  new 
organizations,  thus  accumulating  a  store  of  powers.  Once  organ- 
ized, these  powers  are  at  the  disposal  of  their  possessor,  yet  the 
organized  machine  will  at  some  time  undergo  change,  if  not  more 
or  less  frequently  used.  Without  use  it  may  indeed  finally  disap- 
pear, showing  that  the  caj)acity  for  organization  is  identical  with 
a  facility  of  disorganization. 

III.    THE   ORIGII^   OF   AUTOMATIC   MOYEMEJ^TS. 

Is  any  habit  originated  in  unconsciousness  ?  Those  who  affirm 
this  proposition  point  to  the  movements  of  plants  in  the  extension 


394  METAPHYSICAL  EVOLUTION. 

of  their  tendrils,  and  the  closing  of  some  sensitive  leaves  ;  the 
timely  expansion  of  the  down  of  the  Asclepias  seed,  and  the  in- 
sect-catchinof  habits  of  Brosera  and  Dioncea.  No  one  surely 
attributes  consciousness  to  these.  And  there  are  many  similar 
movements  in  animals  which  are  as  thoroughly  unconsciously 
performed  as  are  those  of  plants,  from  the  first  moment  of  the  ani- 
mal's birth  :  as,  for  instance,  the  involuntary  activities  of  the  cir- 
culatory and  digestive  systems,  etc.  Did  these  originate  in  con- 
sciousness or  unconsciousness  ?  The  answer  to  this  question 
constitutes  the  key  to  the  mysteries  of  evolution,  and  around  it 
the  battle  of  the  evolutionists  of  the  coming  years  will  be  fought. 

It  may  be  asserted  at  the  outset  that  those  habits  whose  origin 
we  have  had  the  opportunity  of  observing  in  ourselves  and  in  other 
animals  were  certainly  acquired  in  consciousness,  and  that  we  do 
not  believe  that  they  could  have  originated  out  of  it.  The  stimuli 
to  action  are  divided  into  the  two  general  classes  of  pleasures  and 
pains,  and  each  stimulus  is  potent  in  proportion  to  the  intensity 
with  which  it  is  consciously  apprehended.  If  many  and  complex 
acts  may  be  performed  automatically,  through  the  organization  of 
special  machinery  in  the  gray  matter  of  the  brain,  it  is  altogether 
reasonable  that  similar  powers  should  be  found  to  be  conferred  on 
gray  nervous  tissues  in  parts  of  the  body  which  are  no  longer  seats 
of  consciousness.  It  is  well  known  that  the  spinal  cord  of  the  head- 
less frog  responds  to  stimuli,  in  the  vigorous  muscular  contractions 
of  the  limbs  which  follow  the  application  of  acid  to  the  skin.  So 
the  ganglionic  centers  of  organic  life  respond  to  their  appropriate 
excitants  ;  the  various  glands  of  the  digestive  system  discharging 
their  contents  into  the  ingesta  at  the  proper  moment,  conscious- 
ness having  no  share  in  the  proceeding.  These  phenomena  are 
more  readily  explained  on  the  theory  of  endowment  than  on  that 
of  physical  movements  ;  since  by  means  of  the  former  the  evident 
design  in  the  movements  is  accounted  for,  while  the  latter  gives  us 
no  clew  to  this  characteristic  feature  of  these  and  all  other  vital 
processes. 

The  lowest  form  of  consciousness  is  common  sensibility  ;  and, 
judging  by  the  resemblance  between  our  own  experience  and  that 
of  the  higher  animals,  the  lowest  of  animals  also  are  not  devoid 
of  this  quality.  The  structureless  jelly  of  Rhizopods,  such  as 
Amoebas,  Gromias,  etc.,  evidently  selects  its  food  with  regard  to 
its  nutritious  qualities,  in  most  instances  preferring  diatoms  and 
desmids  to  sand  and  other  innutritions  substances.     Its  acquisi- 


CONSCIOUSNESS   IN  EVOLUTION.  395 


'o 


tions  in  knowledge  of  articles  of  food  can  only  be  accounted  for 
on  the  hypothesis  of  original,  pleasurable  or  painful,  conscious- 
ness of  the  effects  of  external  and  internal  contact  with  these  sub- 
stances, and  retention  of  the  impression  in  unconsciousness.  The 
impression  reviving  on  the  recurring  of  a  similar  contact,  the  sub- 
stance is  accepted  or  rejected  as  the  former  sensations  were  pleas- 
urable or  painful.  And  this  is  not  incredible,  if,  as  the  researches 
indicate,  the  structure  of  the  protoplasm  of  these  creatures  is  of 
the  same  type  as  that  of  the  bioplastic  bodies  of  the  gray  tissue  of 
the  brain. 

in  accordance  with  this  view,  the  automatic  *^  involuntary " 
movements  of  the  heart,  intestines,  reproductive  systems,  etc., 
were  organized  in  successive  states  of  consciousness,  which  con- 
ferred rhythmic  movements,  whose  results  varied  with  the  ma- 
chinery already  existing  and  the  material  at  hand  for  use.  It  is 
not  inconceivable  that  circulation  may  have  been  established  by 
the  suffering  produced  by  an  overloaded  stomach  demanding  dis- 
tribution of  its  contents.  The  structure  of  the  Coelenterata  offers 
the  structural  conditions  of  such  a  process.  A  want  of  j^ropul- 
sion  in  a  stomach  or  body  sack  occupied  with  its  own  functions 
would  lead  to  a  painful  clogging  of  the  flow  of  its  products,  and 
the  *' voluntary"  contractility  of  the  body  or  tube-wall  being  thus 
stimulated,  would  at  some  point  originate  the  pulsation  necessary 
to  relieve  the  tension.  Thus  might  have  originated  the  "  con- 
tractile vesicle"  of  some  protozoa,  or  contractile  tube  of  some 
higher  animals  ;  its  ultimate  product  being  the  mammalian  heart. 
So  with  reproduction.  Perhaps  an  excess  of  assimilation  in  well- 
fed  individuals  of  the  first  animals  led  to  the  discovery  that  self- 
division  constituted  a  relief  from  the  oppression  of  too  great  bulk. 
With  the  increasing  specialization  of  form,  this  process  would  be- 
come necessarily  localized  in  the  body,  and  growth  would  repeat 
such  resulting  structure  in  descent,  as  readily  as  any  of  tlie  other 
structural  peculiarities.  No  function  bears  the  mark  of  conscious 
origin  more  than  this  one,  as  consciousness  is  still  one  of  the  con- 
ditions of  its  performance.  While  less  completely  "voluntary" 
than  muscular  action,  it  is  more  dependent  on  stimulus  for  its 
initial  movements,  and  does  not  in  these  display  the  unconscious 
automatism  characteristic  of  the  muscular  acts  of  many  other 
functions. 

Bearing  in  mind  the  property  of  protoplasm  to  organize  ma- 
chinery which  shall  work  automatically  in  the  absence  of  con- 


396  METAPHYSICAL  EVOLUTION. 

sciousness,  we  can  glance  at  the  succession  of  vegetable  forms. 
The  active  movements  of  the  primary  stages  of  the  x^lgae  are  well 
known.  After  swimming  actively  through  the  water,  they  settle 
down,  take  root,  and  assume  the  role  of  plants.  The  Aethalium, 
swimming  with  the  movements  of  a  Rhizopod,  has  been  known  to 
take  food  before  establishing  itself  on  the  damp  piles  of  the  tan- 
bark,  where  it  speedily  becomes  a  low  form  of  fungus.  The  ap- 
proximation of  the  lower  forms  of  plants  to  animals  is  notorious. 
The  fungi,  it  is  said,  are  the  only  terrestrial  j)lants  which  live  like 
animals  on  organic  matter,  appropriating  the  humus  of  their  rich 
nidus  in  a  state  of  solution.  ISTow  the  paleontology  of  animals  has 
absolutely  established  the  fact  that  the  predecessors  of  all  charac- 
teristic or  sioecialized  ty|3es  have  been  unspecialized  or  generalized 
types,  ''  neither  one  thing  nor  another."  It  may  then  be  regarded 
as  almost  certain  that  the  ancestors  of  the  present  higher  types 
of  plants  were  more  animal-like  than  they ;  that  the  forms  dis- 
playing automatic  movements  were  more  numerous,  and  the  diffi- 
culty of  deciding  on  the  vegetable  or  animal  nature  of  a  living 
organism  greater  than  it  is  now.  Hence  it  may  be  concluded  that 
*^ animal"  consciousness  has  from  time  to  time  organized  its  ma- 
chinery and  then  disappeared  forever,  leaving  as  result  the  per- 
manent form  of  life  which  we  call  vegetable.  But  it  is  not  to  be 
supposed  that  all  changes  of  structure  cease  with  the  departure  of 
consciousness.  Given  spontaneous  movement  (i.  e.,  growth),  and 
surrounding  conditions,  and  the  resultant  product  must  be  struct- 
ures adapted  to  their  surroundings,  just  as  the  plastic  clay  is  fitted 
to  its  mold.  And  this  is  essentially  the  distinguishing  character 
of  vegetable  teleology  as  compared  with  animal.  In  the  average 
plant  we  see  adaptation  to  the  conditions  of  unconscious  nutrition  ; 
in  the  animal,  adaptation  to  conditions  of  conscious  contact  with 
the  world  under  a  great  variety  of  conditions. 

IT.    GROWTH-FORCE. 

The  active  processes  of  living  beings  are  examples  of  conversion 
of  physical  forces,  only  differing  from  the  conversions  observed  to 
take  place  in  inorganic  bodies,  in  the  nature  of  the  machinery 
which  exhibits  them.  The  construction  of  this  machinerv,  as  in 
its  use  when  finished,  involves  a  conversion  of  force,  the  resultant 
consisting  of  the  attraction  of  nutritious  material  in  definite  new 
directions.  This  determinate  attraction  has  been  regarded  as  a 
distinct  force,  to  which  the  name  of  bathmic  or  growth  force  has 


CONSCIOUSNESS  IN  EVOLUTION.  397 

been  ap2)lied.  It  differs  from  all  the  physical  forces  in  this,  that 
while  they  are  only  exerted  inversely  as  the  square  of  the  distance, 
this  one  is  in  addition  most  excessive  where  pleasure  has  been  ex- 
perienced, and  weakest  where  pain  has  left  its  deepest  traces.  In 
other  words,  its  movements  express  design,  the  essential  condition 
of  which  is  consciousness.  It  is  thus  evident  that  it  differs  utterly 
from  all  other  forces,  although  a  retrograde  metamorphosis  of  mat- 
ter is  as  necessary  for  its  production  as  for  that  of  any  of  the  other 
forces.  Now,  although  the  evidences  that  stimulated  consciousness, 
or  if  you  choose,  mind,  can  modify  structure,  are,  as  matter  of 
observation,  not  very  satisfactory  ;  yet,  since  the  essential  2:)ecul- 
iarity  of  growth-force  is  its  instant  attendance  on  the  needs  of 
consciousness,  it  is  a  permissible  hypothesis  that  its  activity  is 
immediately  due  to  consciousness.  This  activity  is  located  in 
bioplasts  which  do  not  exhibit  consciousness  ;  whetlier  it  co-exists 
with  consciousness  in  brain  bioplasts  is  unknown.  The  successive 
exhibitions  of  this  force,  from  the  low^est  to  the  highest  of  living 
beings,  have  ever  been  additions  to  the  executive  machinery  of  a 
more  and  more  specialized  consciousness.  Thus  it  is  that  its  re- 
sults in  structure  have  ever  become  more  and  more  complex,  that 
is,  composed  of  an  ever-increasing  number  of  parts  in  some  region 
of  the  organism.  Hence  another  point  of  distinction  from  other 
forces  exists,  which  has  been  pointed  out  in  a  previous  paper.  It 
is  quite  evident  that  the  higher  forms  of  life  are  the  result  of  con- 
tinued superaddition  of  one  result  of  growth-force  on  another, 
some  examples  of  subtraction  or  simplification  of  i^arts  being  gen- 
erally accompanied  by  a  great  preponderance  of  additions.  This 
is  evidence  of  the  accumulation  of  the  property  of  producing  this 
kind  of  force,  since  each  successive  addition  imposes  on  the  grow- 
ing animals  a  great  number  of  successive  stages  before  the  process 
reaches  its  termination,  maturity.  This  involves  the  belief  that 
the  property  of  exhibiting  frequent  *' repetitions"  of  growth-ac- 
tivity exists  in  a  higher  degree  in  the  reproductive  bioplasm  of  the 
more  complex  animal  than  in  that  of  the  lower  ones.  This  is  in 
accordance  with  the  fact  of  the  regular  increase  in  relative  com- 
plexity and  bulk  of  the  nervous  system,  which  accompanies  com- 
plexity of  structure  in  other  respects  in  the  ascending  scale  of  ani- 
mals. Thus  this  force  differs  from  all  others,  as  remarked  by  Prof. 
Hartshorne,  in  that  its  expenditure  ultimately  increases  the  amount 
of  its  production,  because  it  constructs  machinery  which  feeds  its 
especial  organs  more  and  more  successfully.     Although  expended 


398  METAPHYSICAL  EVOLUTION. 

by  becoming  energetic,  its  energy  produces  the  means  of  its  own 
increase.  Unlike  the  physical  forces  whose  expenditure  renders 
matter  ever  more  inert,  growth-force  when  expended  adds  mate- 
rial which,  as  a  profitable  addition,  increases  the  power  of  the  cen- 
tral machine  from  which  the  force  emanates,  by  furnishing  an  in- 
creased supply  of  food.* 

Thus  it  is  evident  that  growth-force  is  not  concentric  nor  j)olar 
in  its  activity,  as  are  the  physical  forces,  and  that  its  determina- 
tions are  antagonistic  to  these.  Its  existence  in  the  earth  has 
been  a  succession  of  conquests  over  polar  force,  and,  if  preceding 
assumj^tions  be  true,  the  gradual  progress  presented  by  animals  in 
abandoning  the  symmetrical  forms  exhibited  by  the  lower  types 
has  doubtless  been  due  to  the  constantly  increasing  amount  of 
consciousness. 

V.    THE   DOCTRINE   OF   THE   UXSPECIALIZED. 

It  is,  however,  evident  that  the  directing  power  of  conscious- 
ness is  limited  by  the  nature  of  the  matter  with  which  it  has  to 
deal.  There  are  certain  fundamental  necessities  to  which  it  must 
conform.  No  one  supposes  that  any  degree  of  power  can  make 
twice  two  equal  to  six,  cause  two  solid  substances  to  occupy  the 
same  space  at  the  same  time,  or  make  an  absolutely  solid  sub- 
stance out  of  incompressible  atoms  of  different  forms.  These  in- 
volve the  absurdity  that  something  can  be  made  out  of  nothing, 
or  nothing  out  of  something.  From  the  present  conduct  of  the 
inorganic  world,  it  would  appear  to  possess  properties  which  ren- 
der consciousness  impossible  to  it.  This  is  doubtless  due  to  the 
relations  existing  between  the  atoms  or  molecules  of  which  its 
various  species  consist.  The  movements  it  displays  are  polar. 
The  colloid  molecular  state  is,  so  far  as  this  planet  is  concerned, 
the  only  one  which  we  know  to  be  capable  of  consciousness,  and 
then  only  while  in  a  state  of  active  transformation.  As  we  have 
seen,  when  protoplasm  is  once  organized  and  working  automati- 
cally, consciousness  need  not  be  present ;  and  when  this  is  absent, 
the  rate  of  transformation,  that  is,  the  amount  of  food  consumed, 
is  greatly  lessened.     The  excess  of  expenditure  during  conscious 

*  It  is  incorrect  to   say  that  growth-force  is  "potential"  in  highly  organized- 
types,  as  it  is  undoubtedly  expended  in  the  movement  of  nutritive  pabulum  to  a 
given  locality.     The  maintenance  of  it  in  that  locality  is  due  to  ordinary  molecular 
cohesion,  which  can  only  be  set  free  by  greater  molecular  consolidation. 


CONSCIOUSNESS  IN  EVOLUTION.  399 

activity  over  that  necessary  to  unconscious  activity  is  well  known. 
It  is  thus  evident  that  organization  renders  consciousness  unne- 
cessary, GO  long  as  external  conditions  are  unchanged,  and  most 
probably  a  degree  of  fixity  may  be  attained  which  renders  con- 
sciousness impossible.  The  history  of  the  evolution  of  animal 
types  is  apparently  an  illustration  of  this  truth.  The  relations 
of  the  divisions  of  the  animal  kingdom  are  those  of  the  limbs, 
branches,  and  trunk  of  a  tree.  Although  the  termini  of  the 
branches  are  successively  nearer  the  root  or  starting-point  as  we 
proceed  from  the  apex  downward  or  backward,  yet  the  connec- 
tion is  not  from  end  to  end  of  these.  To  find  this  we  pass  down 
the  limb  to  its  junction  with  the  trunk,  and  trace  the  branches 
from  the  axis  outward.  Thus  with  the  branches  of  the  animal 
kingdom.  Although  the  divisions  Vertebrata,  Mollusca,  Echino- 
dermata,  etc.,  stand  in  an  undoubted  relation  of  succession  to 
each  other,  there  is  no  connection  between  the  highest  representa- 
tive of  one  and  the  lowest  of  another.  It  is  the  lower  or  less 
specialized  forms  of  each  which  exhibit  the  relationship.  Thus, 
among  the  articulates,  the  low  group  of  the  worms  gives  us  con- 
nection with  the  Mollusca  above  by  BracMopoda,  and  the  echino- 
derms  connect  themselves  with  the  Vermes  by  the  less  specialized 
Holothurida.  It  seems  highly  probable  also  that  the  point  of  con- 
tact of  the  Vertebrata  with  these  is  by  one  of  the  lowest  divisions, 
formerly  regarded  as  molluscan,  viz.:  the  Ascidia.  The  same 
principle  holds  good  within  the  great  divisions.  The  most  spe- 
cialized orders  of  Mammalia  are  the  Artiodactyla,  higher  Perisso- 
dactrjla,  the  Carnivora,  Quadrumana,  and  perhaps  Cetacea ;  but 
the  higher  of  these  have  not  been  derived  from  the  lower.  Mod- 
ern investigations  show  that  several  of  them  have  been  derived 
from  a  common  type  of  mammals  of  the  Eocene  period,  wiiich  is 
intimately  connected  with  their  lower  forms,  while  wanting  in 
the  features  which  give  them  their  special  characters.  These  two 
illustrations  serve  to  explain  the  universal  law  of  zoological  affin- 
ity, and  therefore  of  evolution. 

The  conclusion  derived  from  a  survey  of  this  field  is,  that 
structure,  like  habit,  when  once  established,  is  closely  adhered  to, 
and  that  the  movement  of  growth-force  once  determined  or  or- 
ganized becomes  automatic,  i.  e.,  independent  of  consciousness. 
Therefore  a  type  which  reproduces  itself  automatically  becomes 
after  a  time  so  established  as  to  be  incapable  of  radical  change,  in 
consequence  of  a  molecular  fixity  which  precludes  it.     Neverthe- 


400  METAPHYSICAL  EVOLUTION". 

less  susceptibility  to  influences  of  conscious  stimuli  may  remain  in 
some  j)ortions  of  the  organism,  and  thus  subordinate  modifica- 
tions of  structure  have  their  origin.  When  conditions  of  life 
change,  as  they  often  have  done  during  geologic  time,  those 
changes  of  structure  which  are  possible  take  place  under  the 
stimulus  of  roused  consciousness.  But  if  the  changes  be  radical, 
affecting  the  foundation  processes  of  vital  economy,  the  specialized 
forms  must  undoubtedly  perish,  and  the  life  of  the  succeeding 
time  be  derived  from  forms  of  less  pronounced  character.  The 
adaptability  of  generalized  types,  as  to  habits,  and  the  absence  of 
mechanical  peculiarities  in  their  structure,  explain  fully  the  cause 
of  their  standing  in  ancestral  relation  to  all  the  typical  faunse  of 
the  earth. 

Nowhere  is  this  truth  more  remarkably  illustrated  than  in  the 
case  of  man,  the  predominant  mammal  of  the  present  period. 
From  the  generalized  mammalian  fauna  of  the  Eocene,  the  Car- 
nivora  developed  a  highly  organized  apparatus  for  the  destruction 
of  life  and  appropriation  of  living  beings  as  food.  The  cloven- 
footed  and  odd- toed  hoofed  orders  *  are  the  result  of  constantly 
increasing  growth  of  the  mechanical  apjDliances  for  rapid  motion 
over  the  ground  ;  the  former  superadding  exceptional  powers  of 
assimilation  of  innutritions  food.  The  proboscidians  developed 
huge  bulk  and  an  extraordinary  prehensile  organ.  The  Quadru- 
mana  produced  none  of  these  things.  In  respect  to  speed  of  limb 
and  powers  of  digestion,  both  in  function  and  structure,  they  re- 
main nearly  in  the  generalized  condition  from  which  the  other 
orders  of  mammals  have  risen.  The  limbs  and  teeth  of  man  re- 
tain the  characters  of  the  primitive  type.  Yet  but  two  species  of 
proboscidians  remain  ;  the  Perissodactyle  multitudes  are  repre- 
sented by  but  a  few  vanishing  species.  The  day  of  the  Car- 
nivora  has  passed  forever,  and  the  remaining  Artiodactyle  herds 
exist  but  by  the  permission  of  their  master,  man.  But  past  geo- 
logic time  reveals  no  such  abundance  of  true  Quadrumana  as  the 
present  period  displays.  These  animals  were  evidently  unable  to 
compete  with  those  of  other  types  in  seizing  on  the  opjjortuni- 
ties  of  livino^.  Thev  were  excluded  from  the  chase  bv  the  more 
sanguinary  ancestors  of  the  Carnivora,  and  from  the  field  by  the 
multiplying  herds  of  the  swifter  or  more  resistant  hoofed  animals. 
They  possessed  neither  bulk,  nor  speed,  nor  cruelty  to  serve  them 

*  Represented  by  the  ox  and  the  horse. 


CONSCIOUSNESS  IN  EVOLUTION.  40I 

in  the  struggle  for  existence.  So  they,  were  doubtless  compelled 
to  assume  an  arboreal  life,  which  required  little  or  no  modifica- 
tion of  the  limbs  for  its  maintenance,  although  the  ultimate  pro- 
duction of  the  grasping  thumb  from  their  primitive  squirrel-like 
feet  may  be  traced  to  this  mode  of  life.  The  acquisition  of  a 
hand  must  be  regarded  as  the  first  step  in  that  marvelous  acces- 
sion of  experiences  which  is  the  condition  of  mental  develoj)ment. 
And  this  latter  growth  has  taken  the  place  of  all  other  means  of 
conquering  a  position  in  the  world  of  life,  so  that  man  has  even 
retrograded  in  the  efficiency  of  bodily  powers.  He  has  lost  the 
prehensile  quality  of  the  hind  feet,  and  the  special  usefulness  of 
his  canine  teeth.  But  the  competition  among  men  continues  to 
be  such  as  to  render  it  in  the  highest  degree  improbable  that  he 
will,  as  a  species,  lose  the  position  gained,  or  suffer  any  prolonged 
diminution  of  the  power  of  intelligence. 

Now  it  is  obvious  that  the  more  restricted  the  conditions  of  the 
life  of  a  given  animal  type,  the  more  sensitive  it  will  be  to  changes. 
Hence  it  is  that  the  risks  to  the  existence  of  Carnivora,  Artiodac- 
tyla,  Prohoscidia,  etc.,  are  much  greater  than  to  the  omnivorous, 
all-adaptive  order  of  Quadrwnana.  The  same  is  true  of  mind. 
The  greater  the  proportion  of  unconscious  automatism  of  habits, 
the  less  the  power  of  adaptation  ;  and  this  must  be  the  condition 
of  all  animals  whose  structure  is  so  specialized  as  to  place  them 
beyond  reach  of  competition,  or  to  cut  them  off  from  a  wide  range 
of  experiences.  The  greater  the  degree  of  consciousness  of  stim- 
ulus, the  greater  will  be  the  degree  of  adaptability  to  new  rela- 
tions, and  to  such  constant  rousing  the  unspecialized  mind  is 
always  open.  If,  without  strong  natural  weapons,  vigilance  is  the 
price  of  existence  ;  if  not  confined  by  organization  to  a  peculiar 
kind  of  food,  ceaseless  investigation  is  stimulated.  And  these  are 
the  mental  peculiarities  which  distinguish  the  monkeys  among  all 
the  Mammalia. 

The  reverse  of  this  picture  may  now  be  described,  as  has  been 
done  by  Prof.  Vogt.  It  is  well  known  that  the  young  of  many 
parasitic  animals  are  free  and  active,  and  discover  during  migra- 
tion the  localities  to  which  they  afterward  attach  themselves  for 
life.  During  the  early  stages  they  present  the  characteristic  marks 
of  their  order  and  class,  and  in  some  instances  the  males,  remain- 
ing free,  continue  to  do  so.  Such  are  the  Entoconclia  miraMUs, 
the  SaccidincB  and  the  Trematoda  ;  the  first  a  mollusk,  the  second 
a  cirrhiped  crustacean,  the  third  a  worm.     On  their  becoming  at- 

26 


402  METAPHYSICAL  EVOLUTION". 

tached  to  their  host  a  successive  obliteration  of  their  distinctive 
characters  takes  place,  so  that  they  become  so  simplified  as  to  be 
no  longer  referable  to  their  proper  class,  but  susceptible,  as  Prof. 
Vogt  remarks,  of  being  united  in  a  single  division.  A  similar 
process  is  observed  in  the  structural  degeneration  of  the  Lernean 
parasites,  which  are  at  first  free,  but  afterward  become  parasitic 
on  fishes.  There  is  in  this  instance  a  coincidence  between  degen- 
eracy of  structure  and  loss  of  compulsory  activity  :  not  only  is 
every  function  of  their  sluggish  lives  automatically  performed,  but 
consciousness  itself  must  experience  little  stimulus. 

From  what  has  preceded,  it  is  evident  that  automatism  is  at 
once  the  product  and  the  antagonist  of  evolution,  and  that  it  is 
represented  in  structure  by  specialization.  It  appears  also  that 
consciousness  is  the  condition  of  the  inauguration  of  new  habits, 
and  this  is  only  possible  to  structures  which  are  not  already  too 
far  specialized.  This  is  doubtless  true,  whether  osseous  and  mus- 
cular tissue  be  concerned  in  evolution,  or  whether  it  be  nervous 
and  brain  tissue.  Hence  in  the  highest  form  of  development, 
that  of  brain  mechanism,  automatism  is  the  enemy,  and  con- 
sciousness the  condition  of  progress.  As  a  product  of  develop- 
ment, automatism  is  the  condition  of  stationary  existence,  and 
constitutes  its  effective  machinery,  but  every  additional  step  re- 
quires the  presence  of  consciousness.  This  may  be  expressed  in 
the  every-day  language  of  human  affairs,  by  saying  that  routine 
and  progress  are  the  opposite  poles  of  social  economy. 

YI.    THE   OKIGIiq"   OF   COKSCIOUSKESS. 

This  question  has  not  yet  been  touched  upon,  nor  is  it  neces- 
sary to  give  it  prolonged  attention  at  present.  Consciousness  is 
in  itself  inscrutable  to  us,  and  the  contrast  which  it  presents  to 
physical  and  vital  forces  is  the  great  fact  of  life.  It  is  obvious 
enough  that  certain  molecular  conditions  are  essential  to  its  ap- 
pearance ;  drugs  intensify  or  obscure  it ;  concussions  and  lesions 
destroy  it.  It  will  doubtless  become  jDOssible  to  exhibit  a  parallel 
scale  of  relations  between  stimuli  on  the  one  hand,  and  the  de- 
grees of  consciousness  on  the  other.  Yet  for  all  this  it  will  be 
impossible  to  express  self-knowledge  in  terms  of  force.  The  ques- 
tion as  to  whether  the  product  of  the  force  conversion  involved  is 
the  consciousness  itself,  or  only  a  condition  of  consciousness,  may 
receive  light  from  the  following  consideration. 

Nowhere  does   "the  doctrine  of  the  unspecialized"  receive 


CONSCIOUSNESS  IN   EVOLUTION.  403 

greater  warrant  than  in  the  constitution  of  protoplasm.  Modern 
chemistry  refers  compound  substances  to  four  classes,  each  of  which 
is  characterized  by  a  special  formula  of  combination.  These  are 
called  the  hydrochloric-acid  type,  the  water-gas  type,  the  ammonia 
type,  and  the  marsh-gas  type.  These  series  are  defined  by  the 
volumetric  relations  of  their  component  simple  substances  :  thus,  in 
the  first,  a  single  volume  unites  with  an  equal  volume  of  hydrogen  ; 
in  the  second,  two  volumes  of  hydrogen  unite  with  a  single  volume  of 
another  element ;  in  the  third,  three,  and  in  the  fourth,  four  vol- 
umes of  hydrogen  unite  with  the  single  volume  of  other  elements. 
Hence  the  composition  of  these  compounds  is  expressed  by  the  fol- 
lowing formulas — chlorine,  oxygen,  nitrogen,  and  carbon  being 
selected  as  typical  of  their  respective  classes  :  HCl,  HjO,  H3N,  and 
H4O.  Now  it  is  an  interesting  fact  that  protoplasm  is  composed 
of  definite  proportions  of  four  simple  substances,  each  one  repre- 
senting one  of  the  classes  above  named,  or,  in  other  words,  the  ca- 
pacity for  proportional  molecular  combination  which  characterizes 
them.  The  formula  C24N8OH17  expresses  the  constitution  of  this 
remarkable  substance.  Now,  although  the  significance  of  these 
combining  numbers  is  unknown,  there  is  a  conceivable  connection 
between  the  characteristic  peculiarities  of  protoplasm  and  the  na- 
ture of  the  substances  which  compose  it.  It  is  probable  that  these, 
when  in  combination  with  each  other,  exert  a  mutually  antago- 
nistic control  over  each  other's  especial  and  powerful  tendencies  to 
form  stable,  and  hence  dead,  compounds.  It  is  therefore  reason- 
able that  the  terms  **unspecialized"  or  *^ undecided"  should  be 
applicable  to  the  molecular  condition  of  protoplasm,  and  in  so  far 
it  is  a  suitable  nidus  for  higher  molecular  organization,  and  a  ca- 
pacity for  higher  forms  of  force-conversion  than  any  other  known 
substance.  If  also  in  inorganic  types,  as  in  the  organic,  the  gen- 
eralized have  preceded  the  specialized  in  the  order  of  evolution,  we 
are  directed  to  a  primitive  condition  of  matter  which  presented 
the  essentially  unspecialized  condition  of  protoplasm,  without 
some  of  its  physical  features.  We  are  not  necessarily  bound  to 
the  hypothesis  that  protoplasm  is  the  only  substance  capable  of 
supporting  consciousness,  but  to  the  opposite  view,  that  the  proba- 
bilities are  in  favor  of  other  and  unspecialized,  at  present  un- 
known, forms  of  matter  possessing  this  capacity. 

Consciousness  constitutes  then  the  only  apparently  initial  point 
of  motion  with  which  we  are  acquainted.  If  so,  we  are  at  liberty 
to  search  for  the  origin  of  the  physical  forces  in  consciousness,  as 


404  METAPHYSICAL  EYOLUTIOlSr. 

well  as  the  vital ;  their  present  unconscious  condition  being  possi- 
bly due,  as  in  the  case  of  the  vital,  to  automatism  :  the  automa- 
tism being  the  expression  of  the  atomic  type  of  the  substance  ex- 
hibiting it.  And,  doubtless,  the  simple  quantitative  relations  of 
the  lowest  types  of  forces  are  related  to  correspondingly  simple 
geometrical  conditions  of  matter,  both  representing  the  simplest 
grade  of  automatic  action  and  machinery.  We  may  also  suppose 
that  all  of  these  primary  conditions  were  necessary  to  the  produc- 
tion of  protoplasm,  the  only  form  of  matter  known  to  us  in  which 
consciousness  can  persist. 

In  conclusion,  it  is  obvious  that  the  metastatic  condition  of 
protoplasm  necessary  to  the  persistence  of  consciousness  could  not 
be  supported  without  a  constant  source  of  supply  by  assimilation. 
Hence  it  would  appear  that  the  preliminary  creation  of  dead  and 
unconscious  substances  and  organisms  were  a  necessary  antecedent 
to  the  accomplishment  of  this  end  ;  at  least  under  circumstances 
of  temperature  under  which  living  beings  or  protoplasm  exist  on 
this  planet.  Without  the  unconscious  inorganic  and  organic  prod- 
ucts of  nature,  consciousness  could  not  exist  on  the  earth  for  a 
day.  No  animal  can  maintain  consciousness  without  food ;  and 
that  food  must  be,  in  the  main,  protoplasm.  Protoplasm  is  manu- 
factured from  inorganic  matter  by  the  (sujoposed)  unconscious 
protoplasm  of  the  plant.  What  form  of  matter  originally  gave 
origin  to  protoplasm  is  yet  unknown,  but  it  is  obvious  that  the 
ordinary  physical  forces  must  have  existed  as  conditions  of  its 
creation,  since  now  they  are  absolutely  necessary  to  its  persistence. 
Hence  we  may  view  the  succession  of  automatic  activities  some- 
what in  the  light  of  the  fagots  used  by  the  elephant  to  lift  itself 
from  the  well  into  which  it  had  fallen.  One  placed  upon  another 
finally  raised  the  footing  to  an  elevation  which  enabled  the  animal 
to  obtain  its  freedom. 

Consciousness  is  the  essential  condition  of  personality ;  so  that 
in  this  view  of  the  case  we  are  led  to  a  j)rimitive  personality,  al- 
though not  to  what  we  call  life.  And  the  reason  why  this  person- 
ality is  to  us  so  obscure  a  conception  is  probably  to  be  found  in 
the  fact  that  it,  as  well  as  ourselves,  is  conditioned  in  its  rela- 
tions to  matter  by  necessary  laws  of  ^'^mathematical"  truth. 


XIX. 
ON  ARCHJESTHETISM. 

I.    THE   HYPOTHESIS   OF   USE  AND   EFFORT. 

The  claims  of  the  theory  of  Lamarck,  that  use  modifies  struct- 
ure in  the  animal  kingdom,  are  being  more  carefully  considered 
than  heretofore,  and  are  being  admitted  in  quarters  where  they 
have  been  hitherto  neglected  or  ignored.  Eleven  years  ago  I  re- 
stated the  question  as  follows  :  * 

**  The  influences  and  forces  which  have  operated  to  j^roduce 
the  type-structures  of  the  animal  kingdom  have  been  plainlv  of 
two  kinds  :  1.  Originative;  2.  Directive.  The  prime  importance 
of  the  former  is  obvious  ;  that  the  latter  is  only  secondary  in  the 
order  of  time  or  succession,  is  evident  from  the  fact  that  it  con- 
trols the  preservation  or  destruction  of  the  results  or  creations  of 
the  first. 

*^  Wallace  and  Darwin  have  propounded  as  the  cause  of  modi- 
fication in  descent  their  law  of  natural  selection.  This  law  has 
been  epitomized  by  Spencer  as  the  ^survival  of  the  fittest.'  Tiiis 
neat  expression  no  doubt  covers  the  case,  but  it  leaves  the  origin 
of  the  fittest  entirely  untouched,  Darwin  assumes  a  tendency 
to  variation '  in  nature,  and  it  is  plainly  necessary  to  do  this,  in 
order  that  materials  for  the  exercise  of  a  selection  should  exist. 
Darwin  and  Wallace's  law  Is,  then,  only  restrictive,  directive,  con- 
servative, or  destructive  of  something  already  created.  I  propose 
then  to  seek  for  the  originative  laws  by  which  these  subjects  are 
furnished — in  other  words,  for  the  causes  of  the  origin  of  the 
fittest. 

"  It  has  seemed  to  the  author  so  clear  from  the  first  as  to  re- 
quire no  demonstration,  that  natural  selection  includes  no  actively 
progressive  principle  whatever  ;  that  it  must  first  wait  for  the  de- 

*  "The  Method  of  Creation,"  1871,  pp.  2  and  18,  Walker  Prize  Essay,  Proceeds. 
Amer.  Phllos.  Soc,  pp.  230-246. 


406  METAPHYSICAL  EVOLUTION. 

velopment  of  variation,  and  then,  after  securing  the  survival  of 
the  best,  wait  again  for  the  best  to  i^roject  its  own  variations  for 
selection.  In  the  question  as  to  whether  the  latter  are  any  better 
or  worse  than  the  characters  of  the  parent,  natural  selection  in  no 
wise  concerns  itself." 

In  seeking  for  the  causes  of  the  origin  of  variation,  the  follow- 
ing hypothesis  was  proposed  : 

^^  What  are  the  influences  locating  growth -force  ?  The  only 
efficient  ones  with  which  we  are  acquainted  are,  first,  physical 
and  chemical  causes  ;  second,  use  ;  and  I  would  add  a  third,  viz.  : 
effort.  I  leave  the  first  as  not  especially  prominent  in  the  econ- 
omy of  type-growth  among  animals,  and  confine  myself  to  the 
two  following.  The  effects  of  use  are  well  known.  We  can  not 
use  a  muscle  without  increasing  its  bulk  ;  we  can  not  long  use 
the  teeth  in  mastication  without  inducing  a  renewed  deposit  of 
dentine  within  the  pulp-cavity  to  meet  the  encroachments  of  at- 
trition. The  hands  of  a  race  of  laborers  are  always  larger  than 
those  of  men  of  other  pursuits.  Pathology  furnishes  us  with  a 
host  of  hypertrophies,  exostoses,  etc.,  produced  by  excessive  use, 
or  necessity  for  increased  means  of  performing  excessive  work. 
The  tendency,  then,  induced  by  use  in  the  parent,  is  to  add 
segments  or  cells  to  the  organ  used.  Use  thus  determines  the 
locality  of  new  repetitions  of  parts  already  existing,  and  deter- 
mines an  increase  of  growth-force  at  the  same  time,  by  the  in- 
crease of  food  always  accompanying  increase  of  work  done,  in 
every  animal. 

^  ^  But  supposing  there  be  no  part  or  organ  to  use.  Such  must 
have  been  the  condition  of  every  animal  prior  to  the  appearance 
of  an  additional  digit  or  limb  or  other  useful  element.  It  appears 
to  me  that  the  cause  of  the  determination  of  growth-force  is  not 
merely  the  irritation  of  the  part  or  organ  used  by  contact  with 
the  objects  of  its  use.  This  would  seem  to  be  the  remote  cause 
of  the  deposit  of  dentine  in  the  used  tooth  ;  in  the  thickening 
epidermis  of  the  hand  of  the  laborer ;  in  the  wandering  of  the 
lymph-cells  to  the  scarified  cornea  of  the  frog  in  Cohnheim's  ex- 
periment. You  can  not  rub  the  sclerotica  of  the  eye  without 
producing  an  expansion  of  the  capillary  arteries  and  correspond- 
ing increase  in  the  amount  of  nutritive  fluid.  But  the  case  may 
be  different  in  the  muscles  and  other  organs  (as  the  pigment  cells 
of  reptiles  and  fishes)  which  are  under  the  control  of  the  volition 
of  the  animal.     Here,  and  in  many  other  instances  which  might 


ON"   ARCHiESTHETISM.  407 

be  cited,  it  can  not  be  asserted  that  the  nutrition  of  use  is  not 
under  the  direct  control  of  the  will  through  the  mediation  of 
nerve-force.  Therefore  I  am  disposed  to  believe  that  growth- 
force  may  be,  through  the  motive  force  of  the  animal,  as  readily 
determined  to  a  locality  where  an  executive  organ  does  not  exist, 
as  to  the  first  segment  or  cell  of  such  an  organ  already  com- 
menced, and  that  therefore  effort  is,  in  the  order  of  time,  the 
first  factor  in  acceleration." 

A  difficulty  in  the  way  of  this  hypothesis  is  the  frequently 
unyielding  character  of  the  structures  of  adult  animals,  and  the 
difficulty  of  bringing  sufficient  pressure  to  bear  on  them  without 
destroying  life.  But  in  fact  the  modifications  must,  in  most  in- 
stances, take  place  during  the  period  of  growth.  It  is  well 
known  that  the  mental  characteristics  of  the  father  are  trans- 
mitted through  the  spermatozooid,  and  that  therefore  the  molec- 
ular movements  which  produce  the  mechanism  of  such  mental 
characters  must  exist  in  the  spermatozooid.  But  the  material  of 
the  spermatozooid  is  combined  with  that  of  the  ovum,  and  the 
embryo  is  composed  of  the  united  contents  of  both  bodies.  In  a 
wonderful  way  the  embryo  develops  into  a  being  which  resembles 
one  or  both  parents  in  minute  details.  This  result  is  evidently 
determined  by  the  molecular  and  dynamic  character  of  the  origi- 
nal reproductive  cells,  which  necessarily  communicate  their  prop- 
erties to  the  embryo,  which  is  produced  by  their  subdivision. 
Rud.  Hering  has  identified  this  property  of  the  original  cells  with 
the  faculty  of  memory.  This  is  a  brilliant  thought,  and,  under 
restriction,  probably  correct.  The  sensations  of  persons  who  have 
suffered  amputation  shows  that  their  sensorium  retains  a  picture 
or  map  of  the  body  so  far  as  regards  the  location  of  all  its  sensitive 
regions.  This  simulacrum  is  invaded  by  consciousness  whenever 
the  proper  stimulus  is  applied,  and  the  locality  of  the  stimulus  is 
fixed  by  it.  This  picture  probably  resides  in  many  of  the  cells, 
both  sensory  and  motor,  and  it  doubtless  does  so  in  the  few  cells 
of  simple  and  low  forms  of  life.  The  spermatozooid  is  such  a 
cell,  and,  how  or  why  we  know  not,  also  contains  such  an  ar- 
rangement of  its  contents,  and  contains  and  communicates  such 
a  type  of  force.  It  is  probable  that  in  the  brain-cell  this  is  the 
condition  of  memory  of  locality.  If  now  an  intense  and  long- 
continued  pressure  of  stimulus  produces  an  unconscious  picture 
of  some  organ  of  the  body  in  the  mind,  there  is  reason  to  suppose 
that  the  energies  communicated  to  the  embryo  by  the  spermato- 


408  METAPHYSICAL  EVOLUTION'. 

zooid  and  ovum  will  partake  of  tlie  character  of  the  memory  thus 
created.  The  only  reason  why  the  oft-repeated  stories  of  birth- 
marks are  so  often  untrue  is  because  the  effect  of  temporary  im- 
pressions on  the  mother  is  not  strong  enough  to  counterbalance 
the  molecular  structure  established  by  impressions  oftener  re- 
peated throughout  much  longer  periods  of  time. 

The  demonstration  of  the  truth  or  falsity  of  this  position,  so  as 
to  constitute  it  the  true  doctrine  of  evolution,  could  only  be  veri- 
fied from  the  prosecution  of  the  science  of  paleontology.  It  is 
only  in  this  field  that  the  consecutive  series  of  structures  can  be 
obtained  which  show  the  directions  in  which  modification  has 
taken  place,  and  thus  furnish  evidence  as  to  the  causes  of  change. 
The  most  complete  result  of  these  investigations,  up  to  the  present 
time,  has  been  the  obtaining  of  sufficiently  full  series  of  the  Mam- 
malia of  the  Tertiary  period  to  show  their  lines  of  descent.  In 
this  way  the  series  of  modifications  of  their  teeth  and  feet  has 
been  discovered,  and  the  homologies  of  their  parts  been  ascer- 
tained.* Perhaps  the  most  important  result  of  these  investiga- 
tions is  the  following  :  The  variations  from  which  natural  selec- 
tion has  derived  the  persistent  types  of  life  have  not  been  general 
or  even  very  extensive.  They  have  been  in  a  limited  number  of 
directions, f  and  the  most  of  these  have  been  toward  the  increase 
in  perfection  of  some  machine.  They  bear  the  impress  of  the 
presence  of  an  adequate  originating  cause,  directed  to  a  special 
end.  Some  of  the  lines  struck  out  have  been  apparently  inade- 
quate to  cope  with  their  environment,  and  have  been  discon- 
tinued. Others  have  been  more  successful,  and  have  remained, 
and  attained  further  modification. 

The  reader  can  estimate  the  chance  of  the  production  of  an 
especially  adaptive  mechanism  in  the  absence  of  any  pressure  of 
force  directing  growth  to  that  end.  It  appears  to  me  that  the 
probability  of  such  variation  appearing  under  such  circumstances 
is  very  slight  indeed,  and  its  continuance  through  many  geologic 
ages  directed  to  the  perfecting  of  one  and  the  same  machine  still 
smaller.  For  this  reason,  attempts  have  been  made  to  demon- 
strate a  mechanical  cause  for  the  modifications  of  structure  ob- 

*  "  Homologies  and  Origin  of  the  Molar  Teeth  of  the  Mammalia  educabilia." 
Journal  Academy  Nat.  Sciences,  Philadelphia,  March,  1874.  Proceedings  Academy 
Nat.  Sci.,  1865,  p.  22. 

f  See  Hyatt  on  this  point,  *'  Tertiary  Planorbis  of  Steinheim."  Anniv.  Mem. 
Bost.  Soc.  Nat.  Hist.,  1880,  p.  20. 


ON  APwCn^STHETISM.  409 

served.  For  these  I  refer  to  papers  by  Messrs.  Alpheus  Hyatt, 
J.  A.  Ryder  and  myself  :  by  Prof.  Hyatt  ..."  Upon  the  Effects 
of  Gravity  on  the  Forms  of  Shells  and  Animals  ; "  *  Mr.  Ryder 
*'0n  the  Mechanical  Genesis  of  Tooth  Forms  ;"  f  and  '*0n  the 
Laws  of  Digital  Reduction  ;"  ];  by  myself  ''  On  the  Origin  of  the 
Specialized  Teeth  of  the  Oarnivora  ;  "  *  "  On  the  Origin  of  the 
Foot  Structures  of  the  Ungulates ; "  ||  "On  the  Effect  of  Impacts 
and  Strains  on  the  Feet  of  Mammalia."  ^  Now  demonstration  of 
the  meclianical  effects  of  the  application  of  force  to  matter  can 
only  be  obtained  by  observation  of  the  process,  and  this  can  not 
be  seen,  of  course,  by  the  observation  of  fossils.  The  relation  of 
the  observed  facts  to  the  hypothesis  is,  however,  shown  by  the 
above  papers  to  be  so  precise  that  it  only  needs  observation  on  the 
production  of  similar  changes  by  similar  causes  in  living  types  to 
give  us  a  demonstration  by  induction,  which  will  satisfy  most 
minds.  That  such  facts  have  been  observed  among  the  lower  ani- 
mals is  well  known.  The  change  of  form  of  animals  without 
hard  parts,  in  adaptation  to  their  environment,  is  an  every-day 
occurrence. 

That  these  views  are  now  shared  by  many  naturalists  is  be- 
coming every  day  more  evident.  Prof.  E.  Dubois-Raymond  ^  has 
recently  delivered  a  lecture  before  the  physicians  of  the  German 
army,  on  exercise  or  use,  in  which  he  makes  some  important 
admissions.  We  give  the  following  extract  :  "  We  should  be, 
therefore,  free  to  admit,  with  some  appearance  of  reason,  that  the 
vigor  of  the  muscles  of  wings  and  of  digging  feet ;  the  thick 
epidermis  of  the  palm  of  the  hand  and  of  the  sole  of  the  foot ; 
the  callosities  of  the  tail  and  of  the  ischia  of  some  monkeys  ;  the 
processes  of  bones  for  the  insertion  of  muscles ;  are  the  conse- 
quences of  nutritive  and  formative  excitation,  transmitted  by 
heredity."  In  this  position  Prof.  Raymond  is  in  strict  accord 
with  the  Lamarckian  school  of  evolutionists.  But  Prof.  Raymond 
still  clings  to  the  obscurities  of  the  Darwinians,  though  Darwin 
himself  is  not  responsible  for  them,  in  the  following  sentences  : 
"  It  is  necessary  to  admit,  along  with  development  by  use,  develop- 

*  "Proceeds.  Amer.  Assoc.  Adv.  Science,"  1880,  p.  527. 

f  "  Proceedings  Academy  Philadelphia,"  1878,  p.  45  ;  1879,  47. 
X  Loe.  cit.^  1877,  October. 

#  "  American  Naturalist,"  March,  1879,  p.  171. 

II  Loc.  cit,  April,  1881,  p.  269.  ^  Loc.  cit,  July,  1881,  p.  542. 

l  "Revue  Scientifique,"  Paris,  Jan.  28,  1882. 


410  METAPHYSICAL  EYOLUTION. 

ment  by  natural  selection,  and  that  for  three  reasons.  First, 
there  are  innumerable  adaptations — I  cite  only  those  known  as 
mimetic  coloration — which  appear  to  be  only  explicable  by  nat- 
ural selection  and  not  by  use.  Second,  plants  which  are,  in  their 
way,  as  well  adapted  to  their  environment  as  animals,  are  of 
course  incapable  of  activity.  Thirdly,  we  need  the  doctrine  of 
natural  selection  to  explain  the  origin  of  the  capacity  for  exercise 
itself.  Unless  we  admit  that  which  it  is  imj^ossible  to  do  from  a 
scientific  stand-point,  that  designed  structures  have  a  mechanical 
origin,  it  is  necessary  to  conclude  that  in  the  struggle  for  exist- 
ence the  victory  has  been  secured  by  those  living  beings  who  in 
exercising  their  natural  functions  have  increased  by  chance  {^  par 
hasard^)  their  capacity  for  these  functions  more  than  others,  and 
that  the  beings  thus  favored  have  transmitted  their  fortunate  gifts 
to  be  still  further  developed  by  their  descendants." 

To  take  up  first  the  second  and  third  of  these  propositions. 
Prof.  Kaymond  does  not  for  the  moment  remember  that  move- 
ment (or  use)  is  an  attribute  of  all  life  in  its  simplest  forms,  and 
that  the  sessile  types  of  life,  both  vegetable  and  animal,  must,  in 
view  of  the  facts,  be  regarded  as  a  condition  of  degeneration.  It 
is  scarcely  to  be  doubted  that  the  primordial  types  of  vegetation 
were  all  free  swimmers,  and  that  their  habit  of  building  cellulose 
and  starch  is  resjjonsible  for  their  early-assumed  stationary  condi- 
tion. Their  protoplasm  is  still  in  motion  in  the  limited  confines 
of  their  walls  of  cellulose.  The  movements  of  primitive  plants 
have  doubtless  modified  their  structure  to  the  extent  of  their  dura- 
tion and  scope,  and  probably  laid  slightly  varied  foundations,  on 
which  automatic  nutrition  has  built  widely  diverse  results.  We 
may  attribute  the  origi7i  of  the  forms  of  the  vegetable  kingdom 
to  three  kinds  of  motion  which  have  acted  in  conjunction  with 
the  physical  environment ;  first,  their  primordial  free  movements  ; 
second,  the  intracellular  movements  of  protoplasm  ;  third,  the 
movements  of  insects,  which  have  doubtless  modified  the  structure 
of  the  floral  organs.  Of  the  forms  thus  produced,  the  fit  have  sur- 
vived and  the  unfit  have  been  lost,  and  that  is  what  natural  selec- 
tion has  had  to  do  with  it. 

The  origin  of  mimetic  coloration,  like  many  other  things,  is  yet 
unknown.  An  orthodox  Darwinian  attributes  it  to  ^'  natural  selec- 
tion," which  turns  out,  on  analysis,  to  be  '"liasard.'^^  The  survival 
of  useful  coloration  is  no  doubt  the  result  of  natural  selection. 
But  this  can  not  be  confounded  with  the  question  of  origin.     On 


ON   AROH^STHETISM.  411 

this  point  the  Darwinian  is  on  the  same  footing  as  the  old-time 
Creationist.  The  latter  says  God  made  the  variations,  and  the 
Darwinian  says  that  they  came  by  chance.  Between  these  posi- 
tions science  can  perceive  nothing  to  choose. 

I  have  attempted  to  explain  the  relation  which  non-adaptive 
structures  bear  to  the  theory  of  use  and  effort,  in  the  following 
language : * 

*'  The  complementary  diminution  of  growth-nutrition  follows 
the  excess  of  the  same  in  a  new  locality  or  organ,  of  necessity,  if 
the  whole  amount  of  which  an  animal  is  capable  be,  as  I  believe 
[for  the  time  being],  fixed.  In  this  way  are  explained  the  cases 
of  retardation  of  character  seen  in  most  higher  types.  The  dis- 
covery of  truly  complementary  parts  is  a  matter  of  nice  observation 
and  experiment.  Perhaps  the  following  cases  may  be  correctly  ex- 
plained. 

'^  A  complementary  loss  of  growth-force  may  be  seen  in  the  ab- 
sence of  superior  incisor  teeth  and  digits  in  ruminating  Mammalia, 
where  excessive  force  is  evidently  expended  in  the  development  of 
horns,  and  complication  of  stomach  and  digestive  organs.  The 
excess  devoted  to  the  latter  region  may  account  for  the  lack  of 
teeth  at  its  anterior  orifice,  the  mouth ;  otherwise,  there  appears 
to  be  no  reason  why  the  ruminating  animals  should  not  have  the 
superior  incisors  as  well  developed  as  in  the  odd-toed  (Perisso- 
dactyl)  Ungulates,  many  of  which  graze  and  browse.  The  loss  to 
the  osseous  system  in  the  subtraction  of  digits  may  be  made  up  in 
the  development  of  horns  and  horn-cores,  the  horn  sheath  being 
perhaps  the  complement  of  the  lost  hoofs.  It  is  not  proposed  to 
assert  that  similar  parts  or  organs  are  necessarily  and  in  all  groups 
complementary  to  each  other.  The  horse  has  the  bones  of  the 
feet  still  further  reduced  than  the  ox,  and  is  nevertheless  without 
horns.  The  expenditure  of  the  complementary  growth-force  may 
be  sought  elsewhere  in  this  animal.  The  lateral  digits  of  the 
EquidcB  are  successively  retarded  in  their  growth,  their  redaction 
being  marked  in  Hippotlierium,  the  last  of  the  three-toed  horses  ; 
it  is  accompanied  by  an  almost  coincident  acceleration  in  the 
growth-nutrition  of  the  middle  toe,  which  thus  appears  to  be  com- 
plementary to  them." 


*  "Method  of  Creation,"  p.  23,  ISTl. 


412  METAPHYSICAL  EYOLUTIOI^. 


II.    THE   OFFICE   OF   COKSCIOUSi^ESS. 

If  the  law  of  modification  of  structure  by  use  and  effort  be 
true,  it  is  evident  that  consciousness  or  sensibility  must  play  an 
important  part  in  evolution.  This  is  because  movements  of  ani- 
mals are  plainly  in  part  controlled  by  their  conscious  states.  The 
question  as  to  how  many  of  the  actions  of  animals  are  due  to  con- 
scious states  at  once  arises.  It  is  well  known  that  most  of  the 
more  strictly  vital  functions  are  unconsciously  performed.  Not 
only  these,  but  many  acts  which  have  to  be  learned  come  to  be 
performed  in  unconsciousness.  Further,  movements  appropriate 
to  needs  which  arise  at  the  moment,  and  which  are  ordinarily 
termed  voluntary,  because  they  require  the  introduction  of  more 
or  less  of  the  rational  faculty,  are  readily  performed  by  verte- 
brated  animals  deprived  of  a  brain,  through  the  agency  of  the 
spinal  cord  alone.*  The  history  of  the  origin  of  these  movements 
must  then  be  traced. 

The  movements  of  living  beings  generally  possess  the  pecul- 
iarity of  design,  in  which  they  differ  from  the  movements  of  non- 
living bodies.  That  is,  their  actions  have  some  definite  reference 
to  their  well-being  or  pleasure,  or  their  preservation  from  injury 
or  pain,  and  are  varied  with  circumstances  as  they  arise.  This  is 
not  the  case  with  non-living  bodies,  which  move  regardless  of 
their  integrity  or  of  that  of  objects  near  them.  This  characteris- 
tic at  once  suggests  that  some  element  enters  into  them  which  is 
wanting  to  the  movements  of  non-living  masses.  It  has  been 
suggested  that  the  attraction  of  animals  for  their  food  and  their 
repulsion  from  pain  are  derivatives  from  the  attractions  and  repul- 
sions of  inorganic  bodies,  supposed  to  be  the  exhibitions  of  the 
force  called  chemism.  But  this  supposition  does  not  explain  the 
wide  difference  between  the  two  classes  of  acts.  The  adaptation 
to  the  environment  seen  in  organic  acts  is  unknown  to  the  inor- 
ganic world,  while  the  invariable  character  of  the  motions  of  in- 
organic force  is  greatly  modified  in  beings  possessed  of  life. 
Whether  consciously  performed  or  not,  the  acts  of  organic  beings 
resemble  those  of  conscious  beings  actuated  by  instincts  of  hunger, 
reproduction,  and  defense. 

An  explanation  of  these  facts  seems  to  be  offered  by  a  well- 

*  Such  expressions  as  "  unconscious  sensibility  "  and  "  unconscious  will "  are  not 
used  here,  as  being  self -contradictory  in  terms  and  without  meaning. 


ON"  ARCH^STHETISM.  413 

known  phenomenon.  We  know  that  it  is  true  of  ourselves  and 
of  many  other  animals,  that  while  all  new  movements  have  to  be 
learned  by  repeated  attempts,  with  each  succeeding  movement 
the  act  becomes  easier,  and  that  finally  it  can  be  performed  with- 
out requiring  any  attention  whatever.  If  continued,  the  move- 
ment becomes  automatic,  so  that  it  may  be  or  is  performed  in  a 
state  of  unconsciousness.  In  the  words  of  Spencer,  nervous  cur- 
rents move  most  readily  along  accustomed  channels.  Thus  the 
"  habits  "  of  animals  may  be  looked  on  as  movements  acquired 
in  consciousness,  and  become  automatic  through  frequent  repeti- 
tion. Not  only  this,  but  the  organization  thus  produced  in  the 
parent  is  transmitted  to  the  succeeding  generation,  so  that  the 
movements  of  the  latter  are  automatically  and  often  unconsciously 
performed.  This  view  may  be  even  extended  to  the  purely  vital 
functions,  with  every  probability  of  its  being  the  true  explanation 
of  their  origin  and  development.  On  a  former  occasion  *  I  wrote  : 
*^In  accordance  with  this  view,  the  automatic  'involuntary' 
movements  of  the  heart,  intestines,  reproductive  systems,  etc., 
were  organized  in  successive  states  of  consciousness,  which  con- 
ferred rhythmic  movements  whose  results  varied  with  the  ma- 
chinery already  existing  and  the  material  at  hand  for  use.  It  is 
not  inconceivable  that  circulation  may  have  been  established  by 
the  suffering  produced  by  an  overloaded  stomach  demanding  dis- 
tribution of  its  contents.  The  structure  of  the  Coelenterata  offers 
the  structural  conditions  of  such  a  process.  A  want  of  propulsive 
power  in  a  stomach  or  body  sac  occupied  with  its  own  functions, 
would  lead  to  a  painful  clogging  of  the  flow  of  its  i3roducts,  and 
the  *  voluntary '  contractility  of  the  body  or  tube  wall  being  thus 
stimulated,  would  at  some  point  originate  the  pulsation  necessary 
to  relieve  the  tension,  Thus  might  have  originated  the  '  con- 
tractile vesicle '  of  some  protozoa,  or  contractile  tube  of  some 
higher  animals  ;  its  ultimate  product  being  the  mammalian  heart. 
So  with  reproduction.  Perhaps  an  excess  of  assimilation  in  wtII- 
fed  individuals  of  the  first  animals  led  to  the  discoverv  that  self- 
division  constituted  a  relief  from  the  oppression  of  too  great 
bulk.  With  the  increasing  specialization  of  form,  this  process 
would  become  necessarily  localized  in  the  body,  and  growth  would 
repeat  such  resulting  structure  in  descent  as  readily  as  any  of 
the  other  structural  peculiarities.     No  function  bears  the  mark 

*  "  Consciousness  iu  Evolution."     "Penn  Monthly,"  August,  1875,  p.  565. 


414  METAPHYSICAL  EYOLUTION". 

of  conscious  origin  more  than  this  one,  as  consciousness  is  still 
one  of  the  conditions  of  its  performance.  While  less  completely 
*  voluntary  '  than  muscular  action,  it  is  more  dependent  on  stim- 
ulus for  its  initial  movements,  and  does  not  in  these  display  the 
unconscious  automatism  characteristic  of  the  muscular  acts  of 
many  other  functions." 

It  was  not  proposed  in  the  preceding  paragraph  that  the  con- 
tractility of  living  protoplasm  should  be  regarded  as  due  to  con- 
sciousness, but  that  the  location  in  a  particular  place  of  a  contrac- 
tility already  existing  might  be  due  to  that  cause. 

The  preceding  hypotheses  bring  us  to  a  general  theory  of  the 
evolution  of  organic  structures  or  species.  It  is  that  they  are  the 
result  of  movements  long  continued  and  inherited,  and  that  the 
character  of  these  movements  was  originally  determined  by  con- 
sciousness or  sensibility.  It  remains  then  to  consider  the  nature 
of  consciousness. 

It  may  be  mentioned  that  it  is  here  left  open  whether  there  be 
any  form  of  force  which  may  be  especially  designated  as  *^  vital." 
Many  of  the  animal  functions  are  known  to  be  physical  and 
chemical,  and  if  there  be  any  one  which  appears  to  be  less  expli- 
cable by  reference  to  these  forces  than  the  others,  it  is  that  of 
nutrition.  Probably  in  this  instance  force  has  been  so  metamor- 
phosed, through  the  influence  of  the  originative  or  conscious  force 
in  evolution,  that  it  is  a  distinct  species  in  the  category  of  forces. 
Assuming  it  to  be  such,  I  have  given  it  the  name  of  Bathmism 
('^Method  of  Creation,"  1871,  p.  26).  Perhaps  the  contractility 
generally  regarded  as  an  attribute  of  living  protoplasm  may  be  a 
mechanical  phenomenon  dependent  of  course  on  nutrition  ;  or  it 
may  be  the  exhibition  of  a  force  peculiar  to  living  beings  ;  and 
hence  one  of  the  *  vital '  group. 

III.    ARCH^STHETISM. 

The  doctrine  of  evolution  derives  the  organs  of  special  sense 
from  those  of  simple  sensibility  or  touch.  In  other  words,  their 
history  has  been  that  of  other  organs  ;  the  complex  have  been 
derived  from  the  general  and  simple.  There  are  then  generalized 
consciousness  and  specialized  consciousness.  A  number  of  forms 
of  consciousness  multiplies  its  vividness,  the  one  kind  reenforcing 
the  other  by  a  slightly  different  appreciation  of  the  same  thing. 
In  the  case  of  persons  deprived  of  the  sense  of  touch,  the  sense 
of  sight  is  not  sufficient  to  convince  them  of  their  own  existence, 


ON  ARCHiESTHETISM.  415 

as  a  matter  of  intellectual  reflection.  When  there  is  no  nervous 
system  we  must  suppose  sensibility  to  be  generally  distributed 
throughout  the  protoplasmic  substance  of  the  animal.  The  locali- 
zation of  consciousness  must  depend  on  a  localization  of  the  kind 
and  condition  of  protoplasm  which  sustains  it ;  while  in  other 
parts  of  the  body  the  protoplasm  is  modified  in  other  directions 
and  for  other  purposes.  If  this  be  true,  the  nervous  tissue  of  the 
higher  animals  should  retain  the  characters  of  the  lowest  simple 
organisms.  In  point  of  fact  this  is  the  case,  the  nucleated  cell 
being  the  essentially  active  element  in  the  functions  of  brain  and 
nerve,  and  being  more  numerous  in  that  tissue  than  in  any  other. 

The  remarkable  evanescence  of  consciousness  is  one  of  its  most 
marked  characteristics.  It  is  this  peculiarity  which  has  led 
many  thinkers  to  deny  its  existence  in  the  lower  animals,  and  to 
induce  others  to  believe  that  it  can  have  had  but  little  place  among 
the  causes  of  evolution.  Partly  for  the  same  reason  many  biolo- 
gists attempt  to  derive  it  by  metamorphosis  from  some  form  of 
force. 

But  the  nature  of  consciousness  is  such  that  it  can  not  be  de- 
rived from  unconsciousness,  any  more  than  matter  can  be  derived 
from  no  matter,  or  force  from  no  force.  The  *'  unthinkable  dogma 
of  creation  "  (Haeckel)  can  not  be  applied  to  consciousness  more 
than  to  matter  or  force.  It  is  a  thing  by  itself,  and  with  matter 
and  force  forms  a  trio  of  primitive  things  which  have  to  be 
accepted  as  ultimate  facts.  This  is  perfectly  consistent  with  the 
position  that  consciousness  is  an  attribute  of  matter,  and  neither 
more  nor  less  difficult  to  comprehend  than  the  fact  that  force  is 
an  attribute  of  matter.  This  view  is  maintained  in  a  fashion  of 
his  own  by  G.  H.  Lewes.  Prof.  Raymond*  says  in  support  of 
the  same  position  : 

*^  More  temperate  heads  betrayed  the  weakness  of  their  dia- 
lectics in  that  they  could  not  grasp  the  difference  between  the 
view  which  I  opposed,  that  consciousness  can  be  explained  upon  a 
mechanical  basis,  and  the  view  which  I  did  not  question,  but  sup- 
ported with  new  arguments,  that  consciousness  is  bound  to  mate- 
rial antecedents."  This  position  has  been  maintained  by  various 
writers,  among  them  Prof.  Allman  f  and  the  writer.     But  Prof. 

*  Address  on  the  celebration  of  the  Birthday  of  Leibnitz.  "  Pop.  Science  Month- 
ly," Feb.,  1882. 

f  Address  delivered  before  the  British  Association  for  the  Advancement  of 
Science. 


416  METAPHYSICAL  EYOLUTIOK 

Raymond  has  not  found  it  to  be  acceptable  to  his  nearest  contem- 
poraries. He  says  :  "  The  opposition  which  has  been  offered  to 
my  assertion  of  tiie  incomprehensibility  of  consciousness  on  a  me- 
chanical theory,  shows  how  mistaken  is  the  idea  of  the  later  phi- 
losophy, that  that  incomprehensibility  is  self-evident.  It  ap- 
pears, rather,  that  all  philosophizing  upon  the  mind  must  begin 
with  the  statement  of  this  point."  In  stating  this  point  some 
years  ago  we  used  the  following  language  :*  ^^It  will  doubtless 
become  possible  to  exhibit  a  parallel  scale  of  relations  between 
stimuli  on  the  one  hand  and  the  degrees  of  consciousness  on  the 
other.  Yet  for  all  this  it  will  be  impossible  to  express  self-knowl- 
edge in  terms  of  force."  And  again  :  f  *'An  unprejudiced  scru- 
tiny  of  the  nature  of  consciousness,  no  matter  how  limited  that 
scrutiny  necessarily  is,  shows  that  it  is  qualitatively  comparable 
to  nothing  else.  .  .  .  From  this  stand-point  it  is  looked  upon  as 
a  state  of  matter  which  is  coeternal  with  it,  but  not  coextensive." 

It  is  probable  then  that  consciousness  is  a  condition  of  matter 
in  some  peculiar  state,  and  that  wherever  that  condition  of  mat- 
ter exists  consciousness  will  be  found,  and  that  the  absence  of  that 
state  implies  the  absence  of  consciousness.     What  is  that  state  ? 

It  would  be  a  monstrous  assumption  to  suppose  that  conscious- 
ness and  life  are  confined  to  the  planet  on  which  we  dwell.  I 
presume  that  no  one  would  be  willing  to  maintain  such  an  hypoth- 
esis. Yet  it  is  obvious  that  if  there  be  beings  possessed  of  these 
attributes  in  the  planets  Mercury  and  Saturn,  they  can  not  be 
composed  of  protoplasm,  nor  of  any  identical  substance  in  the 
two.  In  the  one  planet  protoplasm  would  be  utterly  disorganized 
and  represented  by  its  component  gases  ;  in  the  other  it  would  be 
a  solid,  suitable  for  the  manufacture  of  sharp-edged  tools.  J;  But 
as  it  is  probable  that  j^rotoplasm  is  adapted  for  the  phenomena  of 
consciousness  by  a  certain  peculiarity  of  its  constitution,  it  seems 
evident  that  other  substances  having  a  similar  peculiarity  may 
also  be  able  to  sustain  it.  I  have  elsewhere  attempted  to  discover 
what  this  is,  in  the  following  language  :  * 

*^ Nowhere  does  ^the  doctrine  of  the  unspecialized '  receive 
greater  warrant  than  in  the  constitution  of  protoplasm.  Modern 
chemistry  refers  compound  substances  to  four  classes,   each  of 

*  "Consciousness  in  Evolution."  "Penn  Monthly,"  July,  1875. 
f  "  The  OrijTin  of  the  Will."  "  Penn  Monthly,"  1877,  p,  439. 
X  Frazer  in  "American  Naturalist,"  1879,  p.  420. 

*  "Consciousness  in  Evolution,"  1S75,  p.  573. 


ON  AECH^STHETISM.  4I7 

which  is  characterized  by  a  special  formula  of  combination. 
These  are  called  the  hydrochloric-acid  type,  the  water-gas  type, 
the  ammonia  type,  and  the  marsh-gas  type.  These  series  are  de- 
fined by  the  volumetric  relations  of  their  component  simple  sub- 
stances :  thus  in  the  first,  a  single  volume  unites  with  an  equal 
volume  of  hydrogen  ;  in  the  second,  two  volumes  of  hydrogen 
unite  with  a  single  volume  of  another  element ;  in  the  third,  three, 
and  in  the  fourth,  four  volumes  of  hydrogen  unite  with  the  single 
volume  of  other  elements.  Hence  the  composition  of  these  com- 
pounds is  expressed  by  the  following  formulas — chlorine,  oxygen, 
nitrogen,  and  carbon  being  selected  as  typical  of  their  respective 
classes  :  HCl,  H2O,  H3N",  and  H4C.  Noav  it  is  an  interesting  fact 
that  protoplasm  is  composed  of  definite  proportions  of  four  simple 
substances,  each  one  representing  one  of  the  classes  above  named, 
or,  in  other  words,  the  capacity  for  proportional  molecular  com- 
bination which  characterizes  them.  The  formula  C24N8OH1T  ex- 
presses the  constitution  of  this  remarkable  substance.  Now,  al- 
though the  significance  of  these  combining  numbers  is  unknown, 
there  is  a  conceivable  connection  between  the  characteristic  pecul- 
iarities of  protoplasm  and  the  nature  of  the  substances  which 
compose  it.  It  is  probable  that  these,  when  in  combination  with 
each  other,  exert  a  mutually  antagonistic  control  over  each  other's 
especial  and  powerful  tendencies  to  form  stable,  and  hence  dead, 
compounds.  It  is  therefore  reasonable  that  the  terms  '  unspecial- 
ized' or -^undecided' should  be  applicable  to  the  molecular  con- 
dition of  protoplasm,  and  in  so  far  it  is  a  suitable  nidus  for  higher 
molecular  organization,  and  a  capacity  for  higher  forms  of  force- 
conversion  than  any  other  known  substance.  If  also  in  inorganic 
types,  as  in  the  organic,  the  generalized  have  preceded  the  spe- 
cialized in  the  order  of  evolution,  we  are  directed  to  a  primitive 
condition  of  matter  which  presented  the  essentially  un specialized 
condition  of  protoplasm,  without  some  of  its  physical  features. 
We  are  not  necessarily  bound  to  the  hypothesis  that  protoplasm  is 
the  only  substance  capable  of  supporting  consciousness,  but  to  the 
opposite  view,  that  the  probabilities  are  in  favor  of  other  and  un- 
specialized,  but  unknown,  forms  of  matter  possessing  this  ca- 
pacity." 

The  condition  of  living  protoplasm  was  also  referred  to  in  the 
following  language  in  a  later  publication  :  * 


*  "  The  Origin  of  the  Will."     "  Pouii  Monthly,"  June,  1877,  p.  439. 

27 


418  METAPHYSICAL  EVOLUTION. 

^^  The  cause  of  tlie  difference  between  conscious  and  uncon- 
scious force  must  be  secondarily  due  to  different  conditions  of 
matter  as  to  its  atomic  constitution  ;  consciousness  being  only 
possible,  so  far  as  we  can  ascertain,  to  matter  which  has  not  fallen 
into  fixed  and  automatic  relations  of  its  atoms." 

Protoplasm  in  the  form  of  food  is  not  conscious ;  and  tissue 
formed  of  protoplasm  is  not  conscious,  excepting  certain  cells 
where  the  forming  process  is  in  action.  Nor  is  consciousness 
present  in  all  cells  where  nutrition  is  active.  From  the  increased 
consumption  of  energy,  and  the  increased  expenditure  of  energy 
(heat,  Lombard)  which  takes  place  during  conscious  processes,  we 
may  well  believe  that  the  decomposition  of  protoj^lasm  is  more 
considerable  in  such  processes  than  in  other  forms  of  nervous  ac- 
tivity. We  can  imagine  simple  nutrition  to  be  a  condition  of  the 
elements  of  this  substance  in  which  the  chemical  force  is  simul- 
taneously combining  and  dissolving  its  combination,  and  that  dur- 
ing the  process  there  is  a  condition  in  which  the  chemism  is  for 
the  time  being  unsatisfied,  though  present.  The  direction  which 
this  nutrition  or  metastasis  takes,  is  due  to  the  arrangement  of  the 
molecules  already  existing  in  the  tissue,  the  new  molecules  taking 
the  form  of  the  old  ones  in  replacement,  so  long  as  no  extraneous 
force  interferes.  That  they  are  rearranged  under  the  influence  of 
consciousness  is  apparent  in  the  origin  of  variations  of  structure 
in  accordance  with  the  views  of  evolution  already  entertained.  It 
is  the  arrangement  of  the  molecules  which  constitutes  the  auto- 
matic machinery  of  nutrition  as  well  as  of  other  activities,  so  that 
consciousness  necessarily  only  appears  in  that  stage  of  nutrition 
while  the  matter  is  in  a  transition  state,  and  unformed.  Whether 
chemism  must  be  regarded  as  suspended,  or  only  unsatisfied,  at 
this  stage,  can  only  be  imagined.  As  non-satisfaction  is  probably 
the  tem|)orary  condition  in  all  nutrition,  it  is  not  unlikely  that  sus- 
pension may  be  the  condition  of  consciousness. 

Perhaps  the  character  of  the  components  of  protoplasm  is  such 
that  the  movements  of  their  atoms,  i.  e.,  their  chemism,  mutually 
interfere  and  destroy  each  other,  as  in  the  cases  of  the  interference 
of  the  waves  of  light  and  sound. 

The  colloid  form  of  protoplasm  is  especially  favorable  to  inter- 
nal movements  which  shall  not  destroy  the  integrity  of  the  mass, 
perhaps  more  so  than  a  gaseous  state  in  a  compound  of  similar  con- 
stitution. It  is,  moreover,  more  favorable  to  the  preservation  of 
molarity  than  a  gas  could  be,  on  account  of  the  ease  with  which 


ON   ARCIIiESTnETISM.  4I9 

it  adheres  to  solid  substances,  and  transports  and  locates  them  as 
part  of  its  external  and  internal  supports.  But  it  is  not  incon- 
ceivable that  under  other  conditions  of  temperature,  etc.,  the 
gaseous  condition  of  matter  jnight  answer  the  same  purpose.  It 
must  be  borne  in  mind,  however,  that  this  is  a  subordinate  ques- 
tion, and  that  the  real  characteristic  of  the  "physical  basis  of  life " 
is  to  be  found  rather  in  its  generalized  dynamic  condition. 

We  must  then  believe  that  wherever  this  generalized  condition 
exists,  consciousness  will  be  present.  As  soon  as  mechanical  or 
chemical  force  appears  in  the  molecules  of  the  sustaining  sub- 
stance, consciousness  disappears.  The  organism  has  taken  the  first 
step  toward  death,  but  is  not  dead,  but  is  anmsthetized.  Constant 
nutrition  is  essential  to  the  performance  of  all  life  functions,  in- 
cluding consciousness,  and  it  is  evident  that  this  is  necessary  to 
the  maintenance  of  the  unspecialized  condition  in  which  the  latter 
appears. 

Is  the  appearance  of  sensibility  on  the  development  of  its  sus- 
taining condition,  evidence  that  the  latter  stands  to  the  former  in 
the  relation  of  cause  and  effect  ?  If  the  view  of  the  pre-existence 
of  consciousness  be  true,  there  is  no  more  relation  of  cause  and 
effect  than  in  the  case  of  the  opening  of  a  door  which  admits  a 
wind.  The  force  expended  in  opening  the  door  is  not  converted 
into  the  energy  exerted  by  the  wind  as  it  enters  the  room.  It 
simply  releases  it,  or  admits  it  to  a  new  field.  It  is,  however,  true, 
that  consciousness  having  once  entered,  a  larger  conversion  of  force 
is  necessary  to  its  ^persistence  than  is  expended  during  its  absence. 
Like  combustion,  which  is  only  communicable  under  suitable  con- 
ditions, consciousness  having  once  been  transmitted  to  a  new  cestJie- 
topliore*  lives  on  it,  and  requires  constant  supplies  of  material  for 
its  sustenance. 

The  hypothesis  of  the  primitive  and  creative  function  of  con- 
sciousness may  be  called  Archmsthetism, 

IV.    PAN^STHETISM. 

It  has  been  the  custom  of  men  from  the  dawn  of  thought  to 
attempt  to  construct  for  themselves  cosmogonies  and  theologies. 
Science  is  yet  far  from  supplying  the  facts  necessary  to  the  con- 
struction of  a  true  system  of  the  universe,  and  philosophy  can  only 
stretch  out  a  little  further  into  the  unknown  by  the  use  of  neces- 

*  -^sthetophore,  a  substance  which  sustains  consciousness. 


420  METAPHYSICAL  EVOLUTIOIN'. 

sary  inference.  In  spite,  however,  of  the  insufficiency  of  the  data, 
men  still  suggest  new  yiews  or  cling  to  old  ones,  and  an  occasional 
flight  into  this  region  of  thought  at  least  brings  the  thinker  into 
sympathy  with  the  thoughts  of  his  fellow-men. 

The  admission  of  the  possibility  of  the  existence  of  conscious- 
ness in  other  forms  of  matter  than  protoplasm,  and  in  other  regions 
than  the  Earth,  lends  countenance  to  a  rational  belief  in  the  so- 
called  ^^supernatural"  (better  called  the  supersensuous)  so  preva- 
lent among  men  in  irrational  forms.  The  question  naturally 
arises.  Is  there  any  generalized  form,  of  matter  distributed  through 
the  universe  which  could  sustain  consciousness  ?  The  presump- 
tion is  that  such  a  form  of  matter  may  well  exist.  Evolution  or 
specialization  has  only  worked  up  part  of  its  raw  material  in  the  or- 
ganic world.  Wherever  primitive  conditions  remain,  there  primi- 
tive organisms  abound.  Protozoa  are  yet  numerous  on  land,  and 
the  Protolatliyhius  inhabits  the  depths  of  the  sea.  Highly  spe- 
cialized forms  of  life  are  in  fact  numerically  a  minority  of  living 
beings.  May  not  this  be  true  also  of  inorganic  beings  ?  It  is 
thought  that  various  celestial  bodies  reiDresent  unfinished  worlds. 
Is  it  not  probable  that  the  grand  sources  of  matter  not  yet  spe- 
cialized into  the  sixty  odd  substances  known  to  us,  may  still  sus- 
tain the  primitive  force  not  yet  modified  into  its  species,  and  that 
this  combination  of  states  may  be  the  condition  of  persistent  con- 
sciousness from  which  all  lesser  lights  derive  their  brilliancy  ? 
There  is  much  to  warrant  such  a  view  in  the  observed  facts  of  life, 
taken  in  connection  with  the  general  course  of  evolution.  More- 
over, that  some  form  of  matter  connects  the  interstellar  S2oaces,  is 
thought  to  be  proved  by  the  transmission  of  light  in  some  cases, 
and  light  and  heat  in  others.  That  such  a  form  of  matter  per- 
vades all  spaces  whatever,  is  the  theory  of  some  physicists.  If  it 
be  so  generalized  as  to  be  capable  of  sustaining  consciousness,  it 
becomes  the  source  from  which  other  substances  derive  it,  so  soon 
as  they,  through  the  energy  of  nutrition,  which  resists  death, 
maintain  the  same  primitive  and  unformed  constitution  capable 
of  exhibiting  it. 

Of  course  there  is  no  evidence  in  our  own  memory  of  the  ex- 
istence of  our  personality  prior  to  our  human  experience.  No 
one  on  awaking  from  unconsciousness  remembers  having  been 
anywhere  in  particular  during  the  interval.  These  facts  may  be 
harmonized  with  the  theory  here  presented,  on  the  supposition 
that  memory  is  lost  on  a  transfer  of  consciousness  from  one  physi- 


ON   ARCH^STHETISM.  421 

cal  basis  to  another.  The  arguments  in  favor  of  a  transfer  of 
consciousness  do  not  sustain  the  idea  of  a  transfer  of  memory. 
Memory  requires  an  arrangement  of  molecules  or  atoms  which 
when  finished  no  longer  exhibits  consciousness.  With  proper 
stimulus,  when  the  proper  kind  of  force  conversion  is  set  up  in 
them,  consciousness  extends  into  them,  and,  taking  their  form, 
produces  reminiscence  or  conscious  memory.  The  molecular 
arrangement  would  be  probably  lost  on  a  transfer  of  conscious- 
ness to  a  new  material  basis.  It  might  then  be  supposed  that  with 
every  such  transfer  a  new  personality  is  established.  Though 
the  correct  definition  of  personality  includes  memory  as  well  as 
consciousness,  when  viewed  as  an  objective  concept,  it  may  be 
questioned  whether  memory  is  necessary  to  the  subjective  belief 
in  one's  own  personality.  Those  insane  persons  who  believe  that 
they  have  lost  their  personality,  and  think  that  they  are  some  one 
else,  nevertheless  recognize  the  fact  that  what  they  now  are  has 
a  continuity  of  existence  with  what  they  once  were.  The  mate- 
rial limitations  of  consciousness  are  the  authors  of  the  kind  of 
personality  it  presents.  A  limitation  or  an  expansion  of  its  range 
would  not  destroy  the  idea  of  personality,  but  would  simply  re- 
strict or  extend  it.  The  possible  confluence  of  many  personalities 
would  not  destroy  them,  but  each  one  would  regard  the  others 
as  additions  to  himself,  and  himself,  therefore,  as  so  much  the 
greater  being. 

As  a  summary  of  the  preceding  conclusions,  the  following 
analysis  of  metaphysical  systems  may  be  given.  It  defines  the 
place  of  the  doctrine  of  archsesthetism,  above  proposed,  as  dis- 
tinguished from  the  opposing  view  of  metsesthetism,  which  is 
held  by  many  monists  : 

I.  Consciousness  ("  spirit  ")  is  independent  of  mattei' Dualism. 

II.  Consciousness  is  an  attribute  of  matter Monism. 

o.  Consciousness  is  primitive  and  a  cause  of  evolution ArcJucsthetism. 

iS.  Consciousness  is  a  product  of  the  evolution  of  matter  and  force. 

Metcesthdism. 


XX. 

ON   CATAGENESIS.* 

I.    THE   EVOLUTIOJ^   OF   ORGANISMS. 

The  general  proposition  that  life  has  preceded  organization  in 
the  order  of  time,  may  be  regarded  as  established.  It  follows  ne- 
cessarily from  the  fact  which  has  been  derived  from  paleontological 
investigation,  that  the  simple  forms  have,  with  few  sporadic  ex- 
ceptions, preceded  the  complex  in  the  order  of  appearance  on  the 
earth.  The  history  of  the  lowest  and  simplest  animals  will  never 
be  known,  on  account  of  their  perishability  ;  but  it  is  a  safe  infer- 
ence from  what  is  known,  that  the  earliest  forms  of  life  were  the 
rhizopods,  whose  organization  is  not  even  cellular,  and  includes 
no  organs  whatever.  Yet  these  creatures  are  alive,  and  authors 
familiar  with  them  agree  that  they  display,  among  their  vital 
qualities,  evidences  of  some  degree  of  sensibility. 

The  following  propositions  were  laid  down  by  Lamarck,  as 
established  by  facts  known  to  him,  in  1809  :  f 

I.  '^In  every  animal  which  has  not  passed  the  term  of  its  de- 
velopment, the  frequent  and  sustained  employment  of  an  organ, 
gradually  strengthening  it,  develops  and  enlarges  it,  and  gives  it 
power  proportional  to  the  duration  of  its  use  ;  whilst  the  constant 
disuse  of  a  like  organ  insensibly  weakens  it,  deteriorates  it,  pro- 
gressively reduces  its  functions,  and  finally  causes  it  to  disappear. 

II.  *^  All  that  nature  acquires  or  loses  in  individuals,  through 
the  influence  of  circumstances  to  which  the  race  has  been  exposed 
for  a  long  time,  either  by  the  predominant  use  of  an  organ  or  by 
the  disuse  of  such  part,  she  preserves  by  generation  among  new 

*  An  address  delivered  before  the  Biological  Section  of  the  American  Associa- 
tion for  the  Advancement  of  Science,  at  Philadelphia,  September  4,  1884,  by  E.  D. 
Cope,  vice-president. 

f  "Philosophic  Zoologique,"  Pt.  I,  p.  235  (Edit.  1830). 


ON   CATAGENESIS.  423 

indiyiduals  wliicli  spring  from  it,  j^rovidod  the  acquired  changes 
be  common  to  both  sexes  or  to  those  which  produce  new  indi- 
yiduals.'' 

The  same  ^proposition  was  previously  enunciated  by  Lamarck 
in  the  following  condensed  form  ('^Recherches  sur  les  Corps 
vivans,"  p.  50)  : 

^^  It  is  not  the  organ,  that  is,  the  nature  and  form  of  the  parts 
of  the  body,  which  have  given  origin  to  its  habits  and  peculiar 
functions,  but  it  is,  on  the  contrary,  its  habits,  its  manner  of  life, 
and  the  circumstances  in  which  individuals  from  which  it  came 
found  themselves,  which  have,  after  a  time,  constituted  the  form 
of  the  body,  the  number  and  character  of  its  organs,  and  the  func- 
tions which  it  possesses." 

Several  years  ago,  not  having  read  Lamarck,  I  characterized 
the  above  hypothesis  as  the  ^Haw  of  use  and  effort,"  *  and  I  have 
subsequently  formulated  the  modus  operandi  of  this  law  into  two 
propositions.  The  first  of  these  is,  that  animal  structures  have 
been  produced,  directly  or  indirectly,  by  animal  movements,  or 
the  doctrine  of  Icinetogenesis  ;  the  second  is,  that  as  animal  move- 
ments are  primitively  determined  by  sensibility,  or  consciousness, 
consciousness  has  been  and  is  one  of  the  primary  factors  in  the 
evolution  of  animal  forms.  This  is  the  doctrine  of  arclicBsfl^ci- 
ism.  The  doctrine  of  kinetogenesis  is  implied  in  the  speculations 
of  Lamarck  in  the  following  language  ('*  Philosophie  Zoologique," 
ed.  1830,  p.  239):  *'With  regard  to  the  circumstances  which 
[Nature]  uses  every  day  to  vary  that  which  she  produces,  one  can 
say  that  they  are  inexhaustible.  The  principal  arise  from  the 
influence  of  climates  ;  from  diverse  temperature  of  the  atmos- 
phere and  of  the  environment  generally ;  from  diversity  of  loca- 
tion ;  from  habits,  the  most  ordinary  movements,  and  most  fre- 
quent actions,"  etc.  The  influence  of  motion  on  development  is 
involved  in  Spencer's  theory  of  the  origin  of  vertebrae  by  strains  ;  \ 
and  I  have  maintained  the  view  that  the  various  agencies  in  pro- 
ducing change  mentioned  by  Lamarck  are,  in  the  case  of  animals, 
simply  stimuli  to  motion.  \  The  immediate  mechanical  effect  of 
motion  on  animal  structure  has  been  discussed  in  papers  by  Eyder, 

*  "  Method  of  Creation,"  "  Proceedings  American  Philosophical  Society,''  1871,  p. 
247. 

\  "Principles  of  Biology,"  II,  p.  195. 

X  "  On  the  Relation  of  Animal  Motion  to  Animal  Evolution,"  "American  Natural- 
ist," Jan.,  1878. 


424  METAPHYSICAL  EVOLUTION". 

Hyatt,  eleven ger,  and  myself,  and  I  have  cited  the  evidence  of 
vertebrate  paleontology  as  conclusively  proving  such  an  effect."  * 

The  object  of  the  present  paper  is  to  pursue  the  question  of  the 
relation  of  sensibility  to  evolution,  and  to  consider  some  of  the 
consequences  which  it  involves.  It  is  scarcely  necessary  to  observe 
that,  in  the  early  stage  which  the  subject  presents  at  the  present 
time,  I  can  only  i^oint  out  the  logical  conclusions  deriyable  from 
facts  well  established  rather  than  any  exj^erimental  discoA^eries  not 
already  known.  And  I  will  say  here  to  those  who  object  to  the 
introduction  of  metaphysics  into  biology,  that  they  can  not  logic- 
ally exclude  the  subject.  As  in  one  sense  a  function  of  nervous 
tissue,  mind  is  one  of  the  functions  of  the  body.  Its  phenomena 
are  everywhere  present  in  the  animal  kingdom.  Moreover,  when 
studied  in  the  inductive,  a  posteriori  method,  metaphysics  is  an 
exact  science.  As  Bain  observes,  it  is  a  good  deal  easier  to  fore- 
tell the  actions  of  a  man  than  those  of  the  weather.  It  is  only 
want  of  familiarity  with  the  subject  which  can  induce  a  biologist 
to  exclude  the  science  of  mind  from  the  field. 

For  the  benefit  of  those  who  are  not  familiar  with  the  doctrine 
of  archaesthetism,  f  I  give  an  outline  of  its  implications.  In  the 
first  place,  the  hypothesis  that  consciousness  had  jolayed  a  leading 
part  in  evolution  would  seem  to  be  negatived  by  the  well-known 
facts  of  reflex  action,  automatism,  etc.,  where  acts  are  often  un- 
consciously performed,  and  often  performed  in  direct  opposition 
to  present  stimuli.  But  while  it  is  well  understood  that  these 
phenomena  are  functions  of  organized  structure,  it  is  believed 
that  the  habits  which  they  represent  were  inaugurated  through 
the  immediate  agency  of  consciousness.  It  is  not  believed  that 
a  designed  act  can  have  been  performed /or  the  first  time  X  without 
consciousness  on  the  part  of  the  animal  of  the  want  which  the 
act  was  designed  to  relieve  or  supply.  This  opinion  accords  with 
our  knowledge  of  ourselves,  and,  by  irresistible  inference,  with  our 
belief  regarding  other  animals.  From  such  familiar  observation 
we  also  know  that  so  soon  as  a  movement  of  body  or  mind  has 
been  acquired  by  repetition,  consciousness  need  no  longer  accom- 
pany the  act.     The  act  is  said  to  be  automatic  when  performed 

*  "  The  Evidence  for  Evolution  in  the  History  of  the  Extinct  Mammalia,"  Am. 
Ass.  Adv.  8ci.,  1883,  p.  32. 

f  "American  Naturalist,"  1882,  p.  454. 

X  The  same  view  is  expressed  by  Ribot,  "  Diseases  of  the  Will,"  p.  38  (Humboldt 
Libr.). 


ON  CATAGENESIS.  425 

witliout  exertion,  either  consciously  or  unconsciously,  and  in  those 
functions  now  removed  from  the  influence  of  the  unconscious 
mind  such  acts  are  called  reflex.  The  origin  of  the  acts  is,  how- 
ever, believed  to  have  been  in  consciousness,  not  only  for  the  rea- 
sons above  stated,  but  also  from  facts  of  still  wider  application. 
The  hypothesis  of  archsesthetism  then  maintains  that  conscious- 
ness as  well  as  life  preceded  organism,  and  has  been  the  jjrimum 
mobile  in  the  creation  of  organic  structure.  This  conclusion  also 
flows  from  a  due  consideration  of  the  nature  of  life.  I  think  it 
possible  to  show  that  the  true  definition  of  life  is,  enei^gy  directed 
hy  sensihility,  or  ly  a  mechanism  luliich  has  originated  under  the 
direction  of  sensiMUty.  If  this  be  true,  the  two  statements  that 
life  has  preceded  organism,  and  that  consciousness  has  preceded 
organism,  are  co-equal  expressions. 

II.    COls'SCIOUSIi^ESS,    EITERGY,    AN'D   MATTER. 

Eegarding  for  the  time  being  the  phenomena  of  life  as  energy 
primitively  determined  by  consciousness,  let  us  look  more  closely 
into  the  characteristics  of  this  remarkable  attribute.  That  con- 
sciousness, and  therefore  mind,  is  a  property  of  matter,  is  a  neces- 
sary truth  which  to  some  minds  seems  difficult  of  acceptance. 
That  it  is  not  an  attribute  of  all  kinds  of  matter  is  clear  enough, 
but  to  say  that  it  is  not  an  attribute  of  any  kind  of  matter  is  to 
utter  an  -unthinkable  proposition.  To  my  mind  the  absence  of 
tridimensional  matter  is  synonymous  with  nothingness  or  abso- 
lute vacuity.  To  say  that  phenomena  have  a  material  basis,  is  for 
me  only  another  way  of  saying  that  they  exist.  It  being  granted 
then  that  consciousness  is  an  attribute  of  matter,  or  a  certain 
behavior  of  matter,  it  remains  to  trace  its  relation  to  energy, 
which  is  here  used  in  the  sense  of  motion.  Consciousness  is  clearly 
not  one  of  the  known  so-called  inorganic  forces.  Objects  which 
are  hot,  or  luminous,  or  sonorous,  are  not,  as  is  well  known,  on 
that  account  conscious.  Consciousness  is  not  then  a  necessary 
condition  of  energy.  On  the  other  hand,  in  order  to  be  conscious, 
bodies  must  possess  a  suitable  temperature,  and  must  be  suitably 
nourished.  So  energy  is  a  necessary  condition  of  consciousness. 
For  this  reason  some  thinkers  regard  consciousness  as  a  form  or 
species  of  energy.  For  my  own  part,  in  classification,  I  prefer  to 
keep  very  different  things  apart.  To  classify  consciousness  with 
heat,  light,  sound,  etc.,  does  violence  to  my  sense  of  fitness  and 
to  all  proper  definitions.     This  is  well  shown  by  Prof.  Clifford  in 


426  METAPHYSICAL  EYOLUTIOX. 

the  following  passage  :  *^  It  will  be  found  excellent  practice,  in  the 
mental  operations  required  by  this  doctrine,  to  imagine  a  train 
the  fore  part  of  which  is  an  engine  and  three  carriages  linked  with 
iron  couplings,  and  the  hind  part  three  other  carriages  linked 
with  iron  couplings  ;  the  bond  between  the  two  parts  being  made 
out  of  the  sentiments  of  amity  subsisting  between  the  stoker  and 
the  guard."  *  This  satire,  whether  intentionally  or  not  on  thfe 
part  of  its  learned  author,  expresses  at  once  the  distinctive  char- 
acter of  consciousness  in  esse  and  the  imjDossibility  of  dissociating 
it  from  energy  in  posse.  For  it  is  sufficiently  clear  that  while  the 
conscious  feelings  of  the  stoker  and  the  guard  could  hy  tJie7nselves 
do  nothing  for  the  train,  such  a  state  is  essential  to  the  energy 
displayed  by  them  when  they  are  at  work  for  its  benefit.  We  all 
understand  the  absurdity  of  such  expressions  as  the  equivalency 
of  force  and  matter,  or  the  conversion  of  matter  into  force.  They 
are  not,  however,  more  absurd  than  the  corresponding  proposition 
more  frequently  heard,  that  consciousness  can  be  converted  into 
energy,  and  vice  versa. 

The  energetic  side  of  consciousness,  however,  may  be  readily 
perceived  by  a  little  attention  to  its  operations.  Acts  j^erformed 
in  consciousness  involve  a  greater  exjDenditure  of  energy  than  the 
same  acts  unconsciously  performed.  The  difficulty  of  a  given 
piece  of  labor  is  in  direct  proportion  to  its  novelty  ;  that  is,  is  in 
direct  proportion  to  the  amount  of  endeavor  we  use  in  its  per- 
formance. This  is  another  way  of  saying  that  the  labor  is  direct- 
ly as  the  consciousness  involved.  Another  evidence  of  the  dynam- 
ic character  of  consciousness  is  its  exclusive  and  therefore  com- 
plementary character.  Two  opposite  emotions  can  not  occupy 
the  mind  at  the  same  moment  of  time.  An  emotion  excludes  all 
high  intellectual  work,  and  vice  versa. 

But  there  is  no  fact  with  which  we  are  more  familiar  than  that 
consciousness  in  some  way  determines  the  direction  of  the  energy 
which  it  characterizes.  The  stimuli  which  affect  the  movements  of 
animals  at  first  only  produce  their  results  by  transmission  through 
the  intermediation  of  consciousness.  Without  consciousness,  edu- 
cation, habits,  and  designed  movements  would  be  impossible.  So 
far  as  we  know,  the  instinct  of  hunger,  which  is  at  the  foundation 
of  animal  being,  is  a  state  of  consciousness  in  all  animals.  This  in- 
contestable fact  is  overlooked  by  the  materialists  properly  so  called. 

*  "  Scientific  Basis  of  Morals,"  Humboldt  Library  Ed.,  p.  21. 


ON"  CATAGENESIS.  427 

On  the  other  hand,  as  consciousness  is  an  attribute  of  matter, 
it  is  of  course  subject  to  the  laws  of  necessity  to  which  matter 
and  energy  conform.  For  instance,  it  can  not  cause  two  solid 
bodies  to  occupy  the  same  space  at  the  same  time,  nor  can  it  add 
one  body  to  one  body  and  thus  make  three  bodies.  No  more  can 
it  make  ten  foot-pounds  of  energy  out  of  five  foot-j^ouuds  of 
energy,  and  it  can  not  abolish  time  more  than  it  can  annihilate 
space.  These  are  fundamental  truths  which  are  overlooked  by  a 
majority  of  mankind.  Moreover,  nothing  is  more  common  than 
to  hear  life  or  mind  spoken  of  as  though  it  of  itself  is  a  "sub- 
stance," and  not,  as  it  should  be,  as  an  attribute  or  condition  of 
substance  or  matter. 

What  is,  then,  the  immediate  action  of  consciousness  in  direct- 
ing energy  into  one  channel  rather  than  another  ?  To  take  an 
illustration  :  Why,  from  a  purely  mechanical  point  of  view,  is  the 
adductor  muscle  of  the  right  side  of  the  horse's  tail  contracted 
to  brush  away  the  stinging  fly  from  the  right  side  of  the  horse's 
body  rather  than  the  left  adductor  muscle  ?  Why  was  the  con- 
traction-provoking energy  deflected  into  the  right  interspinal 
motor  nerves  rather  than  into  those  of  the  left  side  ?  Why  is  the 
ear  of  the  horse  turned  forward  to  catch  tlie  sound  in  front  of 
him  and  backward  to  gather  the  sound  coming  from  behind  ? 
The  first  crude  thought  is,  that  consciousness  supplies  another 
energy  which  turns  aside  the  course  of  the  energy  required  to 
produce  the  muscular  contraction  ;  either  as  the  man  with  the 
rein  in  his  hand  turns  aside  the  horse's  head,  or  as  the  shield  he 
holds  deflects  a  moving  body.  But  consciousness  jt?er  5e,  that  is, 
regarding  it  in  its  proper  and  distinctive  definition,  is  not  itself  a 
force  (=  energy).  How,  then,  can  it  exercise  energy  ?  Certainly 
no  more  than  the  bare  good-will  of  the  train  hands  can  pull  the 
train.  Such  an  explanation  is  to  admit  the  possibility  of  making 
something  out  of  nothing. 

III.    THE    RETROGRADE    METAMORPHOSIS    OF   EifERGY. 

The  key  to  many  weighty  and  mysterious  phenomena  lies  in 
the  explanation  of  the  so-called  voluntary  movements  of  animals. 
I  sav  "so-called,"  because  true  will  is  not  at  all  involved  in  the 
question.  I  mean  the  acts  directed  by  consciousness,  the  acts 
which  would  not  take  place  at  all  if  the  animal  were  unconscious. 
That  there  are  many  such  acts  you  well  know.  The  explanation 
can  only  be  found  in  a  simple  acceptance  of  the  fact  as  it  is,  in 


428  METAPHYSICAL  EVOLUTION. 

the  thesis,  that  energy  can  'be  conscious.  If  true,  this  is  an  ulti- 
mate fact,  neither  more  nor  less  difficult  to  comprehend  than  the 
nature  of  energy  or  matter  in  their  ultimate  analyses.  But  how 
is  such  a  hypothesis  to  be  reconciled  with  the  facts  of  nature, 
where  consciousness  plays  a  part  so  infinitesimally  small  ?  The 
explanation  lies  close  at  hand,  and  has  already  been  referred  to. 
Energy  become  automatic  is  no  longer  conscious,  or  is  about  to  be- 
come unconscious.  That  this  is  the  case  is  matter  of  every-day 
observation  on  ourselves  and  on  other  animals.  "What  the  molec- 
ular conditions  of  consciousness  are,  is  one  of  the  problems  of 
the  future,  and  for  us  a  very  interesting  one.  One  thing  is  cer- 
tain, the  organization  of  the  mechanism  of  habits  is  its  enemy. 
It  is  clear  that  in  animals,  energy,  on  the  loss  of  consciousness,  un- 
dergoes a  retrograde  metamorjohosis,  as  it  does  later  in  the  history 
of  organized  beings  on  their  death.  This  loss  of  consciousness 
is  first  succeeded  by  the  so-called  involuntary  and  automatic  func- 
tions of  animals.  According  to  the  law  of  catagenesis,  the  vege- 
tative and  other  vital  functions  of  animals  and  plants  are  a  later 
product  of  the  retrograde  metamorphosis  of  energy.  With  death, 
energy  falls  to  the  level  of  the  polar  tensions  of  chemism,  and  the 
regular  and  symmetrical  movements  of  molecules  in  the  crystalli- 
zation of  its  inorganic  products.  Let  us  now  trace  in  more  de- 
tail the  energies  displayed  by  animals  and  plants. 

It  has  been  already  advanced  (see  page  425)  that  the  phenom- 
ena of  growth-force,  which  are  especially  characteristic  of  living 
things,  originated  in  the  direction  given  to  nutrition  by  conscious- 
ness and  by  the  automatic  movements  derived  from  it.  There 
remain,  however,  some  other  phenomena  which  do  not  yield  so 
readily  to  this  analysis.  These  are  :  first,  the  conversion  by  ani- 
mals of  dead  into  living  protoplasm ;  second,  the  conversion  of 
inorganic  substances  into  protoplasm  by  plants  ;  and  third,  the 
manufacture  of  the  so-called  organic  compounds  from  the  inor- 
ganic by  plants.  To  these  points  we  may  return  again.  It  is 
also  well  known  that  living  animal  organisms  act  as  producers,  by 
conversion,  of  various  kinds  of  inorganic  eneregy,  as  heat,  light, 
sound,  electricity,  motion,  etc.  It  is  the  uses  to  which  these 
forces  are  put  by  the  animal  organism,  the  evident  design  in  the 
occasion  of  their  production,  that  gives  them  the  stamp  of  organic 
life.  We  recognize  the  specific  ultility  of  the  secretions  of  the 
glands,  the  appropriate  distribution  of  the  products  of  digestion, 
and  adaptation  of  muscular  motion  to  many  uses.     The  increase 


ON  CATAGENESIS.  4,29 

of  heat  to  protect  against  depression  of  temperature  ;  tlie  liglit  to 
direct  the  sexes  to  each  other  ;  the  electricity  as  a  defense  against 
enemies — display  unmistakably  the  same  utility.  We  must  not 
only  believe  that  these  functions  of  animals  were  originally  used 
by  them  under  stimulus,  for  their  benefit,  but,  if  life  preceded 
organism,  that  the  molar  mechanism  which  does  the  work  has 
developed  as  the  result  of  the  animal's  exertions  under  stimuli. 
This  will  especially  apply  to  the  mechanism  for  the  production  of 
motion  and  sound.  Heat,  light,  chemism,  and  electricity  doubt- 
less result  from  molecular  aptitudes  inherent  in  the  constitution 
of  protoplasm.  But  the  first  and  last  production  of  even  these 
phenomena  is  dependent  on  the  motions  of  the  animal  in  obtain- 
ing and  assimilating  nutrition.  For  without  nutrition  all  energy 
would  speedily  cease.  Now  the  motion  required  for  the  obtain- 
ing of  nutrition  has  its  origin  in  the  sensation  of  hunger.  So, 
even  for  the  first  stej)s  necessary  to  the  production  of  inorganic 
forces  in  animals,  we  are  brought  back  to  a  primitive  conscious- 
ness. 

To  regard  consciousness  as  the  primitive  condition  of  energy, 
contemplates  an  order  of  evolution  in  large  degree  the  reverse  of 
the  one  which  is  ordinarily  entertained.  The  usual  view  is,  that 
life  is  a  derivative  from  inorganic  energies  as  a  result  of  high  or 
complex  molecular  organization,  and  that  consciousness  (=  sen- 
sibility) is  the  ultimate  outcome  of  the  nervous  or  equivalent 
energy  possessed  by  living  bodies.  The  failure  of  the  attempts 
to  demonstrate  spontaneous  generation  will  prove,  if  continued, 
fatal  to  this  theory.  Nevertheless  the  order  can  not  be  absolutely 
reversed.  Such  a  proceeding  is  negatived  by  the  facts  of  the 
necessary  dependence  of  the  animal  kingdom  on  the  vegetable, 
and  the  vegetable  on  the  inorganic,  for  nutrition,  and  consequently 
for  existence.  So  the  animal  organism  could  not  have  existed 
prior  to  the  vegetable,  nor  the  vegetable  prior  to  the  mineral. 
The  explanation  is  found  in  the  wide  application  of  the  ^^  doctrine 
of  the  unspecialized,"  *  so  clearly  demonstrated  by  paleontology. 
From  this  point  of  view  creation  consists  in  specialization,  an  ex- 
pression which  describes  the  specific  action  of  the  general  princi- 
ple described  by  Spencer  as  the  conversion  of  the  homogeneous 
into  the  heterogeneous.     To  be  more  explicit,  it  consists  of  the 


*  The  term  specialized,  introduced  into  biology  by  Prof.  Dana,  has  been  used  in 
connection  with  energy  in  creation  by  the  author,  "Penn  Monthly,"  1875,  p.  569. 


430  METAPHYSICAL  EVOLUTION. 

production  of  mechanism  outof  no  mechanism,  of  different  kinds 
of  energy  out  of  one  kind  of  energy.  The  material  basis  of  con- 
sciousness must  then  be  a  generalized  substance  which  does  not 
display  the  more  automatic  and  the  polar  forms  of  energy.  From 
a  physical  standpoint  j^rotoplasm  is  such  a  substance.  Its  insta- 
bility indicates  weakness  of  chemical  energy  also,  which  suggests 
that  the  complexity  of  its  molecule  may  be  due  to  some  form  of 
energy  not  properly  chemical.  The  readiness  with  which  it  un- 
dergoes retrograde  metamorphosis  shows  that  it  is  not  self-sustain- 
ing, and  furnishes  a  good  illustration  of  creation  of  specialized 
substances  by  a  running  down  in  the  scale  of  being.  Loew  and 
Bokorny  *  suggest  that  'Hhe  cause  of  the  living  movements  in 
protoplasm  is  to  be  sought  for  in  the  intense  atomic  movements, 
and  therefore  easy  metamorphosis  of  its  aldehyde  groups  of  com- 
ponents "  ;  the  molecular  movements  becoming  molar,  to  use  the 
language  of  Lester  Ward.  The  position  which  I  now  present  re- 
quires the  reversal  of  the  relations  of  these  phenomena.  General- 
ized matter  must  be  supposed  to  be  capable  of  more  varied  molecu- 
lar movements  than  specialized  matter,  and  it  is  believed  that  the 
most  intense  of  all  such  movements  are  those  of  brain  tissue  in 
mental  action,  which  are  furthest  removed  of  all  from  molar  move- 
ments. From  this  point  of  view,  when  molar  movements  are 
derived  from  molecular  movements,  it  is  by  a  process  of  running 
down  of  energy,  not  of  elevation  ;  by  an  increase  of  the  distance 
from  mental  energy,  not  an  approximation  to  it. 

The  fact  that  the  physical  basis  of  consciousness  is  composed 
of  four  substances,  which  are  respectively  a  monad,  a  dyad,  a 
triad,  and  a  tetrad,  doubtless  has  something  to  do,  as  I  have  sug- 
gested,! with  its  exhibition  of  this  remarkable  attribute.  It  might 
be  supposed  that  the  presence  of  carbon  had  the  effect  of  restrain- 
ing the  chemical  and  physical  molecular  tendencies  of  the  three 
other  substances.  From  this  standing-ground  we  may  imagine 
that  other  substances  besides  protoplasm  might  support  conscious- 
ness and  life.  In  other  parts  of  the  universe,  other  substances 
they  would  have  to  be,  if  consciousness  exist  there. 

The  manner  m  which  protoplasm  is  made  at  the  present  tinie 
is  highly  suggestive.     It  is  manufactured  by  living  plants  out  of 

*  "  Die  chcmische  Kraftquelle  in  Icbenden  Protoplasma."  von  0.  Loew  u.  T.  Bo- 
korny,  Munich,  1882,  L 

t  "Penn  Monthly,"  1875,  p.  574. 


ON   CATAGENESIS.  43I 

inorganic  matter,  the  hydrogen,  carbon,  nitrogen,  and  oxygen 
contained  in  the  atmosphere  and  in  the  earth.  As  dead  plants 
will  not  perform  this  function,  this  action  is  regarded  as  in  some 
way  due  to  the  presence  of  life.  The  energy  peculiar  to  living  pro- 
toplasm, and  derived  primarily  in  part  only  from  the  sun's  rays, 
directs  energy  so  that  the  complex  molecular  aggregation  proto- 
plasm is  the  result.  This  is  the  only  known  method  of  manufact- 
ure from  inorganic  matter  of  this  substance.  The  first  piece  of 
protoplasm  had,  however,  no  paternal  protoplasm  from  which  to 
derive  its  being.  The  protoplasm-producing  energy  must,  there- 
fore, have  previously  existed  in  some  form  of  matter  not  proto- 
plasm. This  is  also  suggested  by  the  fact  that  it  really  antagonizes 
the  chemical  forces,  and  might  be  called,  from  this  fact,  anticliem" 
ism.  The  protoplasm-sustaining  energy  of  animal  protoplasm 
may  be  a  less  energetic  derivative,  or  vice  versa.  In  terms  of  the 
theory  of  catagenesis,  the  plant  life  is  a  derivative  of  the  primi- 
tive life,  and  it  has  retained  enough  of  the  primitive  quality  of 
self-maintenance  to  prevent  it  from  running  down  into  forms  of 
energy  which  are  below  the  life  level ;  that  is,  such  as  are  of  the 
inorganic  chemical  type,  or  the  crystalline  physical  type.  A  part 
of  the  energy  does  so  run  down,  as  can  be  seen  in  the  few  auto- 
matic movements  of  plants,  and  the  phosphorescence  of  some. 
Also  symmetrical  crystals  are  made  by  some.  But  M.  Pasteur 
has  shown  *  that  whenever  the  crystals  are  of  the  organic  type, 
i.  e.,  contain  carbon,  they  are  not  symmetrical  but  are  unilateral, 
or,  as  he  terms  them,  dissymmetrical.  This  indicates  that  the 
presence  of  carbon  has  restrained  a  little  the  absolute  symmet- 
rical automatism  of  the  formative  force. 

IV.    ORIGIN"   OF   LIFE   ON"   THE   EARTH. 

If,  then,  some  form  of  matter  other  than  protoplasm  has  been 
capable  of  sustaining  the  essential  energy  of  life,  it  remains  for 
future  research  to  detect  it,  and  to  ascertain  whether  it  has  long 
existed  as  part  of  the  earth's  material  substance  or  not.  The 
heat  of  the  earlier  stages  of  our  planet  may  have  forbidden  its 
presence,  or  it  may  not.  If  it  were  excluded  from  the  earth  in 
its  first  stages  we  may  recognize  the  validity  of  Sir  William 
Thomson's  suggestion  that  the  physical  basis  of  life  may  have 
reached  us  from  some  other  region  of  the  cosmos  by  transporta- 


*  "Revue  Scientifique,"  1884,  Jan.,  p.  2. 


432  METAPHYSICAL  EYOLUTIOK 

tion  on  a  meteorite.  If  protoplasm  in  any  form  were  essential  to 
the  introduction  of  life  on  our  planet,  this  hypothesis  becomes  a 
necessary  truth.  Here  let  me  refer  to  the  fact  that  hydrocar- 
bonaceous  substances  have  been  discoyered  in  meteorites.  Here 
also  the  remarkable  discovery  of  Huggins  claims  attention.*  This 
veteran  spectroscopist  has  detected  the  lines  of  some  hydrocar- 
bon vapor  in  the  spectra  of  interplanetary  spaces.  The  signifi- 
cance of  this  discovery  is  at  once  perceived  if  we  believe  that 
hydrocarbons  are  only  produced  under  the  direction  of  life.f 

Granting  the  existence  of  living  protoplasm  on  the  earth,  there 
is  little  doubt  that  we  have  some  of  its  earliest  forms  still  with  us. 
From  these  simplest  of  living  beings  both  vegetable  and  animal 
kingdoms  have  been  derived.  But  how  was  the  distinction  be- 
tween the  two  lines  of  development,  now  so  widely  divergent, 
originally  produced  ?  The  process  is  not  difficult  to  imagine. 
The  original  plastid  dissolved  the  salts  of  the  earth  and  appro- 
priated the  gases  of  the  atmosphere  and  built  for  itself  more  pro- 
toplasm. Its  energy  was  sufficient  to  overcome  the  chemism  that 
binds  the  molecules  of  nitrogen  and  hydrogen  in  ammonia,  and  of 
carbon  and  oxygen  in  carbonic  dioxide.  It  apparently  communi- 
cated to  these  molecules  its  own  method  of  being,  and  raised  the 
type  of  energy  from  the  polar  non-vital  to  tlje  adaptive  vital  by 
the  process.  Thus  it  transformed  the  dead  mineral  world,  j^er- 
haps  by  a  process  of  invasion,  as  when  a  fire  communicates  itself 
from  burning  to  not  burning  combustible  material.  Thus  it  has 
been  doing  ever  since,  but  it  has  redeposited  some  of  its  gathered 
stores  in  various  non-vital  forms.  Some  of  these  are  in  organic 
forms,  as  cellulose  ;  others  are  crystals  imprisoned  in  its  cells  ; 
while  others  are  amorphous,  as  waxes,  resins,  and  oils.  But  con- 
sciousness a]3parently  early  abandoned  the  vegetable  line.     Doubt- 


*  See  address  of  C.  W.  Siemens,  Prest.  British  Ass.  Adv.  Science,  1882  ;  "  Nature/' 
1882,  p.  400. 

•}■  Says  Mr.  S.  F.  Peckham  ("American  Journal  of  Science  and  Arts,"  1884,  p. 
105),  on  the  origin  of  bitumens:  "These  chemical  theories  [of  the  origin  of  bitu- 
men] are  supported  by  great  names,  and  are  based  upon  very  elaborate  researches, 
but  they  require  the  assumption  of  operations  nowhere  witnessed  in  nature  or  known 
to  technology.  .  .  .  In  the  chemical  processes  of  nature  complex  organic  com- 
pounds pass  to  simpler  forms,  of  which  operation  marsh  gas,  like  asphaltum,  is  a 
resultant,  and  never  the  crude  material  upon  which  decomposing  forces  act." 

The  fact  that  many  organic  compounds  are  now  produced  in  the  laboratory, 
does  not  prove  that  such  substances  can  be  produced  without  the  exercise  of  a  spe- 
cies of  energy  different  from  the  inorganic  types  with  which  we  are  acquainted. 


OlSr  CATAGENESIS.  433 

less  all  the  energies  of  vegetable  protoplasm  soon  became  automatic. 
The  plants  in  general,  in  the  persons  of  their  protist  ancestors, 
soon  left  a  free-swimming  life  and  became  sessile.  Their  lives 
thus  became  parasitic,  more  automatic,  and  in  one  sense  degen- 
erate. 

The  animal  line  may  have  originated  in  this  wise.  Some  indi- 
vidual protists,  perhaps  accidentally,  devoured  some  of  their  fel- 
lows. The  easy  nutrition  which  ensued  was  probably  pleasura- 
ble, and  once  enjoyed  was  repeated,  and  soon  became  a  habit. 
The  excess  of  energy  thus  saved  from  the  laborious  process  of 
making  j^rotoplasm  was  available  as  the  vehicle  of  an  extended 
consciousness.  From  that  day  to  this,  consciousness  has  aban- 
doned few  if  any  members  of  the  animal  kingdom.  In  many  of 
them  it  has  specialized  into  more  or  less  mind.  Organization 
to  subserve  its  needs  has  achieved  a  multifarious  development. 
There  is  abundant  evidence  to  show  that  the  permanent  and  the 
successful  forms  have  ever  been  those  in  which  motion  and  sensi- 
bility have  been  preserved,  and  most  highly  developed. 

This  review  of  the  history  of  living  organisms  has  been  epito- 
mized in  the  following  language:  *^  Evolution  of  living  types  is 
then  a  succession  of  elevation  of  platforms,  on  which  succeeding 
ones  have  built.  The  history  of  one  horizon  of  life  is  that  its 
own  completion  but  prepares  the  way  for  a  higher  one,  furnish- 
ing the  latter  with  conditions  of  a  still  further  development. 
Thus  the  vegetable  kingdom  died,  so  to  speak,  that  the  animal 
kingdom  might  live,  having  descended  from  an  animal  stage  to 
subserve  the  function  of  food  for  animals.  The  successive  types  of 
animals  first  stimulated  the  development  of  the  most  susceptible 
to  the  conflict,  in  the  struggle  for  existence,  and  afterward  fur- 
nished them  with  food." 

V.    CATAGEN"ESIS   OF   IXORGAIN'IC   ENERGY. 

If  the  principles  adopted  in  the  preceding  pages  be  true,  it  is 
highly  probable  that  all  forms  of  energy  have  originated  in  the 
process  of  running  down  or  specialization  from  the  primitive 
energy. 

In  the  department  of  physics  I  am  not  at  home,  and  touch 
upon  it  merely  to  carry  out  to  a  necessary  conclusion  the  hy- 
pothesis presented  in  the  preceding  pages.  It  may  be  that  physi- 
cists and  chemists  may  find  value  in  the  suggestions  which  come 
from  the  side  of  biology.  A  cursory  perusal  of  the  general  hy- 
28 


434  METAPHYSICAL  EVOLUTION. 

potheses  current  in  these  departments  shows  that  the  door  is 
wide  open  to  receive  light  from  this  quarter.  What  can  be  offered 
here  is  of  the  vaguest,  yet  it  may  suggest  thought  and  research 
in  some  minds. 

In  the  first  i^lace,  it  is  highly  probable  that  one  of  the  problems 
to  be  solved  by  the  physicists  of  the  present  and  future  is  that  of 
a  true  genealogy  of  the  different  kinds  of  energy.  In  this  con- 
nection a  leading  question  will  be  the  determination  of  the  essen- 
tial differences  between  the  different  forms  of  energy  and  the 
material  conditions  which  cause  the  metamorphosis  of  one  kind 
of  energy  into  another. 

In  constructing  a  genealogy  of  energies,  it  must  be  observed 
that  we  will  probably  obtain  not  a  single  line  of  succession,  but 
several  lines  of  varying  lengths.  It  must  also  be  remembered 
that,  as  in  the  forms  of  the  material  world,  which  are  their  expres- 
sion, a  greater  or  less  extensive  exhibition  of  all  the  types  remains 
to  the  present  day. 

That  the  tendency  of  purely  inorganic  energy  is  to  '*run 
down,"  in  all  excejot  possibly  some  electric  operations,  is  well 
known.  Inorganic  chemical  activity  constantly  tends  to  make 
simpler  compounds  out  of  the  more  complex,  and  to  end  in  a 
satisfaction  of  affinities  which  can  not  be  further  disturbed  excej)t 
by  access  of  additional  energy.  In  chemical  reaction  the  prefer- 
ence of  energy  is  to  create  solid  precipitates.  In  the  field  of  the 
physical  forces  we  are  met  by  the  same  phenomenon  of  running 
down.  All  inorganic  energies  or  modes  of  motion  tend  to  be  ulti- 
mately converted  into  heat,  and  heat  is  being  steadily  dissipated 
into  space.  Therefore  the  result  has  been  and  will  be  the  creation 
of  the  mineral  kingdom  ;  of  the  rocks  and  fluids  that  constitute 
the  masses  of  the  worlds. 

The  process  of  creation  by  the  retrograde  metamorphosis  of 
energy,  or,  what  is  the  same  thing,  by  the  specialization  of  energy, 
may  be  called  catagenesis.  It  may  be  denied,  however,  that  this 
process  results  in  a  specialization  of  energy.  The  vital  energies 
are  often  regarded  as  the  most  special,  and  the  inorganic  as  the 
most  simple.  If  we  regard  them,  however,  solely  in  the  light  of 
the  essential  nature  of  energy,  i.  e.,  power,  we  must  see  that  the 
chemical  and  physical  forces  are  most  specialized.  The  range  of 
each  species  is  absolutely  limited  to  one  kind  of  effect,  and  their 
diversity  from  each  other  is  total.  How  different  this  from  the 
versatility  of  the  vital  energy  !     It  seems  to  dominate  all  forms  of 


ON   CATAGENESIS.  435 

conversion  of  energy,  by  the  mechanisms  which  it  has,  by  evolu- 
tion, constructed.  Thus,  if  the  inorganic  forces  are  the  products 
of  a  primitive  condition  of  energy  which  had  the  essential  qhar- 
acteristics  of  vital  energy,  it  has  been  by  a  process  of  specializa- 
tion. As  we  have  seen,  it  is  this  specialization  which  is  every- 
where inconsistent  with  life. 

With  these  preliminary  remarks  we  may  now  consider  very 
tentatively  the  relations  of  the  different  kinds  of  energy  to  each 
other  and  to  consciousness.  In  practice  it  is  sometimes  difficult 
to  draw  the  line  between  conscious  and  unconscious  states  of 
energy.  One  reason  is  that,  although  a  given  form  of  energy 
may  be  unconscious,  consciousness  may  apprehend  the  action  by 
perceiving  its  results.  The  distinction  is  rendered  clearer  by 
the  reflection  that  we  can  perceive  by  sight  or  touch  any  action 
of  the  body  of  whatever  character  The  energy  of  the  conscious 
type  is  therefore  altogether  mental.  The  relations  may  be  ex- 
pressed as  follows  : 

A.  Designed  (always  molecular).  Examples. 

I.  Conscious. 

1.  Involving  effort "  Voluntary  "  acts. 

n    -Ki  ^  •       ^  -        tc    ^  \  Passive  perception. 

2.  Not  involvmc^  effort „, 

(  Conscious  automatism. 

II.  Unconscious. 

3.  Involving  mental  process Unconscious  automatic. 

4.  Not  involving  mental  process Eefiex. 

B.  Not  designed. 

I.  Molecular. 

5.  Electric, 

6.  Chemical,    ) 

7    Ph    '    1       \  Crystallific  and  non-crystallific. 

II.  Molar. 

8.  Cosmic. 

The  only  strictly  molar  energies  of  the  above  list  are  the  cos- 
mical  movements  of  the  heavenly  bodies.  The  others  are  molec- 
ular, although  they  give  rise  to  molar  movements,  as  those  of  the 
muscles,  of  magnetism,  etc.  Some  molar  movements  of  organic 
beings  are  not,  in  their  last  phases,  designed  ;  as  those  produced 
by  nervous  diseases. 

The  transition  between  the  organic  and  the  inorganic  energies 
may  be  possibly  found  in  the  electric  group.  Its  influence  on  life, 
its  production  of  contractions  in  protoplasm,  and  its  resemblance 
to  nerve  force,  are  well  known.     It  also  compels  chemical  unions 


436  METAPHYSICAL  EVOLUTION. 

otherwise  impracticable,  thus  resembling  the  energy  of  the  pro- 
toplasm of  plants,  whose  energy  in  actively  resisting  the  disinte- 
grating inorganic  forces  of  nature  is  so  well  known.  Perhaps  this 
type  of  force  is  an  early-born  of  the  primitive  energy,  one  which 
has  not  descended  so  far  in  the  scale  as  the  chemism  which  holds 
so  large  a  part  of  nature  in  the  embrace  of  death. 

Vibration  is  inseparable  from  our  ideas  of  motion  or  energy, 
not  excluding  conscious  energy.  There  are  reasons  for  supposing 
that  in  the  latter  type  of  activity  the  vibrations  are  the  most  rapid 
of  all  those  characteristic  of  the  forces.  A  center  of  such  vibra- 
tions in  generalized  matter  would  radiate  them  in  all  directions. 
With  radiant  divergence  the  wave  lengths  would  become  longer, 
and  their  rate  of  movement  slower.  In  the  differing  rates  of  vibra- 
tions we  may  trace  not  only  the  different  forms  of  energy,  but 
diverse  results  in  material  aggregations.  Such  may  have  been 
the  origin  of  the  specialization  of  energy  and  of  matter  v/hich 
we  behold  in  nature. 

Such  thoughts  arise  unbidden  as  a  remote  but  still  a  legitimate 
induction  from  a  study  of  the  wonderful  phenomenon  of  animal 
motion  ;  a  phenomenon  everywhere  present,  yet  one  which  re- 
treats, as  we  pursue  it,  into  the  dimness  of  the  origin  of  things. 
And  when  we  follow  it  to  its  fountain  head,  we  seem  to  have 
reached  the  origin  of  all  energy,  and  it  turns  upon  us,  the  king 
and  master  of  the  worlds. 


XXI. 

THE   OEIGIN  OF   THE   WILL. 

I.  THE  defikitio:n"  of  the  will. 

Defikitioks  of  tlie  term  '"Will,"  as  we  find  them  in  meta- 
physical writers,  are  not  identical ;  and  much  apparent  difference 
of  opinion  depends,  as  usual,  on  this  diversity  of  statement.  Locke 
regards  the  concepts  *^  will  "and  **  freedom  "as  entirely  distinct 
in  their  nature,  and  not  essentially  related  to  each  other.  He  says  : 
*^  Freedom  belongs  as  little  to  the  will,  as  swiftness  to  sleep,  or 
squareness  to  virtue.  Freedom  to  do  is  one  power,  will  to  do  is 
another  :  will,  a  power  of  the  mind  exerting  dominion  over  some 
part  of  a  man  by  employing  it  in  or  withholding  it  from  any  par- 
ticular action  ;  freedom,  again,  a  power  which  a  man  has  to  do  or 
to  forbear  doing  any  particular  action."  It  appears  that  what 
Locke  here  denominates  will  is  that  common  activity  of  the  mind 
which  expresses  itself  in  action,  which  may  be  readily  considered 
apart  from  the  question  of  choice.  This  doubtless  expressed  some- 
thing to  the  metaphysicians  of  that  time,  but  merely  signifies  to 
the  physiologist  of  the  present  day  the  movement  derived  from 
the  metamorphosis  of  nutritive  material  in  the  arterioles  of  the 
brain,  which  when  consciously  performed  are  called  thoughts  and 
feelings,  and  are  the  necessary  precursors  of  a  class  of  muscular 
acts.  The  question  of  will  properly  so  called  is  not  yet  entered 
on  at  this  point.  Dr.  Willis  *  elaborates  Locke's  position  in  the 
following  language  :  *^  But  there  is,  in  fact,  no  one  particular 
primitive  faculty  that  wills  in  the  human  mind  ;  will  is  a  general 
term,  and  belongs  to  and  is  expressive  of  the  activity  of  each  of 
the  primitive  faculties  of  our  nature  ;  the  benevolent  faculty  being 
active,  causes  us  to  will  to  do  good  and  charitable  offices  ;  the  rev- 
erential faculty  being  active,  to  will  to  feel  respectfully  or  rever- 
ently ;  the  musical  faculty  active,  to  will   to  sing  or  hear  music, 

*  "Benedict  do  Spinoza:  his  Life,  Correspondence,  and  Ethics,"  1S70,  p.  145. 


438  METAPHYSICAL  EVOLUTION. 

etc.  ;  and  the  Vvilling  here  is  necessary  ;  but  whether  we  yield  to 
the  impulse  of  the  benevolent,  reverential,  or  musical  faculty,  and 
indulge  therein  their  various  willings,  is  not  so  ;  here  we  are  free, 
and  can  yield  or  abstain  as  we  list."  This  passage  renders  it  the 
more  clear  that  the  latter  part  of  Locke's  statement,  in  which  he 
defines  freedom,  is  that  in  which  he  really  refers  to  the  will  as 
generally  understood  ;  and  Dr.  Willis's  assertion  of  the  existence 
of  our  ability  'Ho  yield  or  abstain  as  we  list,"  grants  all  that  the 
advocate  of  'Hhe  freedom  of  the  will"  could  desire. 

The  modern  automatic  school  only  avoid  discarding  the  term 
will  altogether  by  using  it  in  the  sense  of  Locke's  definition. 
They  make  it  merely  the  conscious  mental  activity  that  precedes 
the  act ;  the  direction  of  that  activity  being  necessary  in  its  char- 
acter;  i.  e.,  the  result  of  impinging  stimuli.  In  other  words,  on 
the  automatic  theory,  the  spontaneous  activity  of  the  body  is 
directed  or  deflected  by  stimuli,  whose  ultimate  form  depends  on 
the  existing  mental  machinery  through  which  they  pass.  There 
is  avowedly  no  room  for  a  self-determination  in  such  a  process, 
and  its  existence  is  therefore  denied  by  this  school.  Inasmuch  as 
a  faculty  of  self-determination  is  what  is  here  understood  by  the 
term  will,  and  the  question  in  the  present  article  is  whether  there 
be  or  be  not  such  a  faculty,  the  inquiry  to  which  we  address  our- 
S3lves  is  whether  a  human  will  exist  or  not.  Says  Dr.  Carpenter  :  * 
''  The  psychologist  may  throw  himself  into  the  deepest  waters  of 
speculative  inquiry  in  regard  to  the  relation  between  his  mind 
and  its  bodily  instrument,  provided  that  he  trusts  to  the  inherent 
buoyancy  of  that  great  fact  of  consciousness  that  zue  have  within 
us  a  self'determiiiing  poiuer  which  we  call  will, "  The  existence  of 
such  a  faculty  is  in  these  words  assumed  by  Dr.  Carpenter,  but  I 
have  looked  in  vain  in  his  writings  for  a  demonstration  of  the 
truth  of  this  position.  The  same  is  true  of  the  works  of  many 
other  metaphysicians. 

Will  may  be  considered  in  two  aspects  :  first,  as  a  control  over 
the  origin  of  mental  or  bodily  movements  ;  and  second,  as  a  con- 
trol over  the  direction  which  those  movements  take.  The  latter 
case  is  the  one  chiefly  considered  here,  as  the  one  involved  in  cus- 
tomary definitions  of  human  will. 

It  need  scarcely  be  added  that  the  concept  will  is  an  abstrac- 
tion from  supposed  special  exhibitions  of  it,  and  represents  a  sup- 
posed mental  property. 

*  "  Mental  Physiology,"  p.  28. 


THE   ORIGIN"  OF  THE   WILL.  439 

II.    THE    iq^ATUEE    OF    ACTIONS. 

The  discussion  between  the  advocates  of  the  freedom  of  the  will 
on  the  one  hand,  and  those  of  the  doctrine  of  necessity  on  the 
other,  has  often  been  obstructed  by  a  petitio  principii,  which 
yields  the  case  to  the  latter  side  at  the  outset.  This  is  the  dictum 
which  has  often  passed  unchallenged  by  both  parties,  that  "■  human 
action  is  the  product  of  the  strongest  inducement,"  or,  otherwise 
stated,. that  "the  will  is  the  result  of  a  balancing  of  opposing 
motives,"  or  that  "the  will  obeys  the  strongest  motive."  This  is 
simply  the  statement,  in  reversed  order,  of  what  we  might  suppose 
without  examination  to  be  a  general  truth,  viz.  :  that  the  motives 
which  precede  the  acts  which  we  observe  are  stronger  than  all 
others  at  the  time.  If  this  proposition  be  true  without  qualifica- 
tion, there  is  no  further  need  of  discussion,  since  it  involves  the 
negation  of  freedom,  or  of  a  power  of  choosing.  But  as  such,  it 
is  an  assumption  in  advance  of  a  conclusion  in  the  case  under  con- 
sideration ;  a  begging  of  the  question  in  a  clear  sense.  Such  a 
position  can  only  be  adopted  as  a  result  of  the  fullest  investigation 
into  the  phenomena ;  it  can  not  be  accorded  before  examination 
into  the  facts. 

But  the  statement  may  be  admitted  with  this  important  qualifi- 
cation, by  which  the  argument  is  transferred  to  another  stage  of 
the  subject,  viz. :  that  we  do  not  thereby  explain  why  the  induce- 
ments to  act  thus  and  so,  do,  in  many  obvious  cases,  overbalance 
all  others  in  a  given  human  mind.  This  inquiry  is  not  fruitless, 
so  long  as  we  have  before  us  every  day  examples  of  men  acting 
differently  under  identical  circumstances.  If  there  be  any  "  lib- 
erty," it  is  exercised  at  the  point  of  permitting  inducements  or 
motives  of  one  kind  to  occupy  the  mind  to  the  exclusion  of  those 
of  another  kind  ;  and  secondly,  such  occupation  being  granted, 
freedom  might  be  exercised  in  removing  restraint  from  the  press- 
ure of  the  present  motive,  so  that  the  act  can  take  place.  If  there 
be  no  inherent  power  of  controlling  the  attention,  and  none  of 
restraining  the  pressure  of  motive,  then  there  is  no  will  in  any 
proper  sense  of  the  word,  and  man  is  an  irresponsible  automaton. 
The  proof  or  disproof  of  this  proposition  must,  however,  be  the  end, 
not  the  beginning,  of  the  discussion. 

An  inquiry  into  the  origin  of  actions  must  be  preceded  by  an 
examination  into  the  nature  of  the  acts  themselves.  The  follow- 
ing classification  is  offered,  as  expressing  as  nearly  as  possible  their 


44:0  METAPHYSICAL  EVOLUTIOK 

relations  to  the  general  developmental  position  of  active  beings, 
without  any  pre-suppositions  as  to  their  automatic  or  voluntary 
character.  It  is  necessarily  assumed  that  all  acts  are  performed 
with  reference  to  the  acquisition  of  pleasure  or  the  avoidance  of 
pain  ;  in  other  words,  that  all  acts  are  due  to  motive,  and  are  the 
expression  of  design  on  the  part  of  the  actor.  This  is  as  true  of 
the  simplest  as  of  the  most  complex  actions  of  animals,  whether 
consciously  or  unconsciously  performed.  The  movement  of  the 
Amoeha  in  ingulfing  a  Diatom  in  its  jelly,  is  as  much  designed  as 
the  diplomacy  of  the  statesman,  or  the  investigations  of  the  stu- 
dent. And  the  motive  may  be  the  same  in  all  three  cases  ;  viz. : 
hunger.  But  as  the  unconscious  acts  have  been  probably  derived 
from  conscious  ones  by  organization,  a  fundamental  classification 
must  first  recognize  their  relations  to  the  two  necessary  terms  of 
consciousness,  the  subject  and  the  object.  All  actions  may  then 
be  divided  into  two  classes ;  those  which  are  performed  witli  the 
design  of  securing  the  pleasure  of  the  subject,  and  those  whose 
motive  is  to  secure  pleasure  for  the  object  as  distinct  from,  i.  e., 
opposed  to,  that  of  the  subject.  The  tendencies  thus  defined  have 
been  named,  in  other  connections,  the  appetent  and  the  altruistic, 
and  these  names  may  be  preserved  as  equally  appropriate  for  the 
present  purpose.  Actions  of  the  appetent  class  difl'er  according  to 
the  developmental  grade  of  the  animal  displaying  them,  or  the 
grade  of  the  organ  of  the  body  to  which  they  are  proper.  In  their 
simplest  form  they  are  mechanical  movements,  following  a  stimu- 
lus without  the  intervention  of  any  rational  process  ;  the  end  being 
attained  by  movements,  whose  directions  are  determined  by  me- 
chanical or  physical  laws  only.  Such  acts  belong  to  the  lowest 
type  of  animals,  and  are  also  seen  in  the  organic  functions  of  all 
animals  ;  they  may  be  called  the  anoesthetic  division.  They  may 
be  performed  consciously  or  unconscicasly.  Acts  of  another  order 
are  those  which,  while  due  to  stimuli,  are  directed  by  a  process  of 
ratiocination.  They  are  higher  than  those  of  the  previous  order, 
because  they  successfully  accomplish  their  object  under  changing 
circumstances,  to  which  they  adapt  themselves  as  the  others  can 
not.  Like  them  they  may  be  performed  in  consciousness  or  in 
unconsciousness,  or  in  a  still  higher  state  of  the  mind,  that  of  self- 
consciousness.  The  last  condition  is  only  possible  to  animals  of  a 
high  order  of  intelligence,  since  it  not  only  demands  an  exercise 
of  the  rational  faculty,  with  reference  to  objects,  but  also  with 
reference  to  itself — the  subject.     These  three  groups  form  the 


TEE   OPJGIX   OF  THE   WILL.  441 

rational  order.  The  unconscious  actions  of  both  tlie  anaesthetic 
and  rational  kinds  are  called  '^  reflex  ;  "  and  all  of  them  are  **  auto- 
matic," in  so  far  as  they  are  performed  without  will ;  terms  more 
fully  defined  in  the  following  pages.  The  process  of  intellection 
in  unconsciousness  is  called  unconscious  cerebration. 

Actions  of  the  second  great  class,  the  altruistic,  demand  for 
their  performance  the  attributes  necessary  for  the  highest  of  the 
appetent  class.  They  require  intelligence  enough  for  the  percep- 
tion of  what  is  the  pleasure  of  the  object,  and  self-consciousness, 
to  know  that  that  pleasure  is  inconsistent  with  its  own,  or  subject- 
ive pleasure. 

The  arrangement  may  be  summarized  as  follows  : 
L  Appetent  class. 

-.A        J.1    i.-     (  Unconscious  (reflex). 

1.  Anaesthetic.  1  ^^        . 

(  Oonscious. 

(  Unconscious  (reflex). 

2.  Eational.      I  Conscious. 

(  Self-conscious. 
II.  Altruistic  class  ;  rational  and  self-conscious. 

Under  the  definition  of  will  above  given,  it  can  not  be  present 
in  unconscious  or  reflex  actions,  and  the  inquiry  is  limited  to  the 
conscious  groups  exclusively.  It  may  then  be  well  to  add  a  few 
words  on  the  nature  of  consciousness. 

This  faculty  is  here  understood  in  its  broadest  sense,  namely, 
subjective  perception.  The  term  consciousness  expresses  the 
knowledge  by  the  subject  of  the  effects  of  stimuli  on  itself,  which 
ranges  all  the  way  from  the  mere  sense  of  contact  to, the  sense  of 
an  idea.  An  unprejudiced  scrutiny  of  the  nature  of  conscious- 
ness, no  matter  how  limited  that  scrutiny  necessarily  is,  shows  that 
it  is  qualitatively  comparable  to  nothing  else.  The  attempts  to 
correlate  it  with  the  physical  forces  have  so  far  been  utter  failures, 
although  the  vital  forces,  to  which  it  gives  direction,  are  evidently 
not  excluded  from  the  laws  of  quality  and  quantity.  The  com- 
mon hj^pothesis  that  consciousness  is  the  product  of  evolution 
appears  to  the  writer,  in  view  of  this  primary  fact,  to  be  irra- 
tional ;  while  the  converse,  that  evolution  is  a  product  of  con- 
sciousness, is  far  more  likely  to  receive  ultimate  demonstration. 
From  this  stand-point  it  is  looked  upon  as  a  state  of  matter 
which  is  co-eternal  with  it,  but  not  co-extensive.  Itself  in  its 
totality  a  reservoir  of  force,  it  is  the  source  of  all  physical  and 
vital  forces,  with  which  it  has  therefore  an  equivalency  of  quanti- 


442  METAPHYSICAL  EVOLUTION. 

ties,  but  not  of  qualities.  Tlie  cause  of  the  difference  between 
conscious  and  unconscious  force  must  be  secondarily  due  to  differ- 
ent conditions  of  matter  as  to  its  atomic  constitution  ;  conscious- 
ness being  only  possible,  so  far  as  we  can  ascertain,  to  matter 
which  has  not  fallen  into  fixed  and  automatic  relations  of  its 
atoms.  The  condition  appears  to  be  one  of  tension,  in  which 
the  automatic  (crystalline)  tendencies  antagonize  each  other,  the 
material  being  all  the  while  in  the  metastatic  condition  of  nutri- 
tion. This  idea  is  parallel  to  that  of  Heraclitus,  who  held  that 
the  essence  of  all  things  lay  in  per|)etual  modification,  a  universal 
becoming,  an  eternal  emergence  and  disappearance. 

In  accordance  with  the  preceding  views,  the  relations  between 
consciousness  and  matter  are  thus  depicted  as  of  a  mutually  ne- 
cessary character,  the  movements  of  conscious  force  involving  con- 
sequences to  itself  from  which  the  properties  of  matter  necessarily 
preclude  its  escape. 

If  we  trace  the  consciousness  of  animals  to  such  an  origin,  it 
may  be  asked.  Why  have  not  such  beings  the  powers  and  perfec- 
tions of  their  source,  in  quality  if  not  in  quantity  ?  The  answer  to 
this  query,  in  view  of  the  fact  that  they  have  not  such  qualities, 
is  only  to  be  found  in  an  investigation  of  the  nature  of  memory. 
The  absence  of  memory  of  the  past  would  be  equivalent  to  igno- 
rance ;  while  a  new  material  vehicle  might  render  memory  possi- 
ble for  the  future,  and  thus  education,  under  new  surroundings, 
create  diverse  beings  from  a  primal  common  source. 

We  must  include  in  our  estimation  of  the  distributions  of  con- 
sciousness and  forces  not  our  planet  alone,  nor  our  system  only, 
but  the  universe.  Hence  Sir  William  Thompson's  idea,  that  con- 
sciousness ("life")  was  originally  exotic  to  our  earth,  is  an  alto- 
gether permissible  hypothesis. 

If  there  be  such  a  state  of  consciousness  as  will,  it  must  have 
appeared  in  course  of  the  evolution  of  animals,  at  some  point  in 
the  series  of  the  stages  of  progress  through  which  their  mind  has 
passed.  Yet  it  is  maintained  by  some  thinkers  that  the  doctrine 
of  evolution  necessarily  excludes  the  idea  of  freedom  from  the 
nature  of  the  minds  thus  produced.  The  case  is,  however,  in- 
volved in  that  of  consciousness,  and  the  investigation  of  it  must 
proceed  in  the  same  manner.  If  it  has  been  shown  that  will  does 
exist  in  connection  with  evolution,  we  must  proceed  to  discover, 
if  possible,  the  relation  between  the  two  facts. 

The  proof  of  the  existence  of  a  freedom,  power  of  choice,  or 


THE   ORIGIN   OF  THE   WILL.  443 

will,  is  found  in  the  origin  of  the  altruistic  class  of  acts,  which  are 
probably  only  possible  to  the  human  species.  These  have  been 
above  defined  as  those  in  which  the  pleasure  of  the  object,  as  dis- 
tinct from,  and  therefore  opposed  to,  that  of  the  subject,  is  the 
design  of  the  act.  This  definition  excludes  acts  for  the  benefit  of 
others  in  which  the  actor  is  also  gratified,  since  the  motive  may 
be  in  that  case  the  pleasure  of  the  subject.  No  doubt,  many  gen- 
erous acts  are  of  this  character,  but  they  were  not  such  the  first 
time  they  were  performed,  since  experience  of  their  pleasurable 
character  had  not  then  been  acquired,  and  the  evidence  of  all 
past  experience  was  of  a  diametrically  opposite  character.  In 
other  words,  the  motives  already  organized  in  the  mind  of  the 
subject  were  all  in  favor  of  the  subject.  The  laws  of  evolution 
render  the  introduction  of  a  new  element  of  character  at  this  point 
absolutely  necessary.  It  is  well  known  that  the  development  of 
mind,  and  through  it  of  all  the  acts  of  the  first  or  appetent  class, 
has  been  due  to  the  pursuit  of  pleasure  and  avoidance  of  pain  on 
the  part  of  the  subject.  The  pursuit  of  an  opposite  course,  by 
animals  whose  pleasures  and  pains  are  those  of  the  successful  ful- 
fillment of  the  necessary  functions  of  life,  or  the  reverse,  would 
insure  their  speedy  extinction.  Their  survival  has  been  due  to 
their  prompt  discrimination  of  favorable  and  unfavorable  con- 
ditions through  their  sensibilities,  and  the  human  species,  as  the 
product  of  evolution,  displays  these  sensibilities  in  their  highest 
form.  Under  these  circumstances  it  is  obvious,  since  none  but 
the  inherited  motives,  with  refinements  due  to  more  complex 
circumstances,  can  be  found  in  his  mind,  that  without  the  inter- 
vention of  will,  an  altruistic  act  is  impossible. 

It  has  also  been  pointed  out  that  such  can  only  be  performed 
by  a  being  capable  of  the  highest  state  of  consciousness,  i.  e.,  self- 
consciousness  ;  in  other  words,  by  a  being  capable  of  recognizing 
its  own  mental  states.  Under  such  circumstance  only  can  it  dis- 
tinguish the  mental  states  of  a  being  apart  from  itself,  toward 
whom  the  altruistic  act  is  directed. 

It  being  then  conceded  that  will  is  exhibited  in  certain  human 
actions,  it  becomes  important  to  determine,  if  possible,  the  condi- 
tions under  which  it  appeared  in  the  course  of  the  evolution  of 
man. 

III.    THE    ELEMENTS    OF   MIND. 

Prior  to  considering  the  origin  of  states  of  mind,  it  is  neces- 
sary to  go  over  the  well-trodden  field  of  its  original  constitution. 


444  METAPHYSICAL  EVOLUTION. 

There  are  three  primary  conditions  of  consciousness^  which 
naturally  grade  into  each  other,  viz.:  pain,  indifference,  and 
pleasure.  Consciousness  is  of  one  or  the  other  of  these  types  in 
all  animals.  The  constant  flow  of  activity,  either  in  movements 
of  the  whole  body  or  of  particular  2:)arts  of  the  body,  has  brought 
animals  from  their  beginning  into  contact  with  other  bodies, 
either  at  rest,  or  animated  by  active  forces,  as  light  and  heat, 
which  have  varied  their  sensations,  rendering  them  more  positive 
in  each  of  the  three  directions  named.  These  sensations  soon 
cease,  leaving  consciousness  where  it  was,  but  not  without  marks 
of  their  former  presence  in  the  organism.  They  are  recorded, 
and  continue  in  unconsciousness  so  long  as  the  organism  remains 
unchanged.  This  is  the  first  part  of  memory,  i.  e.,  retention. 
Under  the  influence  of  what  is  called  cohesion,  the  impressions 
may  be  returned  to  consciousness  in  a  less  distinct  form  by  the 
occurrence  of  new  impressions  which  have  some  near  relation 
with  them  as  to  time,  place,  or  qualities  of  other  kinds.  This  is 
the  second  part  of  memory,  or  reminiscence.  The  sum  of  the 
impressions  which  are  necessar}'  to  memory  constitutes  experi- 
ence. It  is  evident  that  reminiscence  is  pleasurable  or  painful, 
as  the  experiences  recalled  were  pleasurable  or  painful.  Another 
quality  is  rendered  possible  by  the  two  faculties  of  retention  and 
cohesion,  viz.:  classification.  This  consists  of  a  re-arrangement 
of  retained  impressions  in  accordance  with  different  kinds  of  co- 
hesions, i.  e.,  different  kinds  of  likenesses.  The  products  of 
classification  may  be  brought  into  consciousness  just  as  sensible 
impressions  are  revived  ;  but  unlike  these,  they  constitute  in  their 
totality  a  new  experience  of  internal  origin.  When  a  cohesion 
between  two  circumstances  is  due  to  a  repeated  experience  of  the 
one  as  following  the  other,  men  entertain  the  idea  that  one  is 
necessary  to  the  other.  From  memory  of  the  necessary  results 
of  our  own  activity,  we  have  come  to  regard  necessary  sequences 
as  the  result  of  activity  somewhere.  If  activity  be  discerned  in 
the  first  of  two  coherent  events,  we  regard  it  as  a  cause  of  the 
second  :  if  the  first  be  passive,  the  idea  of  cause  does  not  arise  in 
connection  with  it,  but  in  some  other  active  agent.  Finally,  all 
processes  involving  reminiscences  are  less  distinct  than  the  original 
impressions.  Spencer  calls  the  former /«m^,  the  loiter  distinct ; 
the  faint  order  are  the  processes  of  reason  ;  the  distinct,  of  per- 
ception. 

Whether  these  processes  are  pleasurable,  painful,  or  indifferent, 


THE   ORIGIN   OF  THE   WILL.  445 

depends  on  the  characteristics  of  the  reminiscences  wliich  are 
their  subjects.  As  the  reminiscence  is  less  distinct  than  the  origi- 
nal impression,  so  there  comes  to  be,  as  pointed  out  by  Spencer,  a 
faint  order  of  pleasures  and  pains,  which,  with  the  indifferent  class, 
form  the  material  of  the  processes  of  reason.  These  mental  states 
of  pleasurable  and  painful  consciousness  constitute  that  primary 
diyision  of  the  mind,  the  feelings  or  affections,  as  distinguished 
from  the  intellect. 

The  feelings  co-exist  with  intellectual  operations  of  all  grades 
of  complication,  since  pleasures  and  pains  are  states  which  follow 
all  kinds  of  activities,  and  therefore  also  reminiscences.  To  seek 
pleasure  and  to  avoid  pain  constitutes  the  business  of  the  lives  of 
all  conscious  organisms  ;  and  hence  the  feelings,  as  derived  from 
exjDeriences,  are  the  directive  and  often  originative  conditions  of 
movements  or  actions.  In  animals  with  higher  intellectual  powers, 
the  general  classification  of  experiences  of  given  objects  or  actions 
results  in  a  higher  order  of  the  mental  feelings,  which  are  called 
likes  and  dislikes.  When  these  forms  of  consciousness  assume  an 
intense  condition  due  to  stimuli,  they  become  emotions  or  pas- 
sions. 

These  details  are  entered  into  in  order  to  show  that  the  feel- 
ings in  their  various  grades  are  the  motives  of  action  in  all  ani- 
mals, from  the  Amcela  to  man.  In  the  former  they  are  mere 
reminiscences  ;  in  the  latter  they  are  so  generalized  as  to  become 
enduring  principles  of  action,  which  put  the  intellect  to  every 
conceivable  labor.  And  it  is  evident,  from  this  foundation  fact, 
how  the  intellect  itself  has  been  constructed.  The  activity  stimu- 
lated by  the  feelings  has  resulted  in  new  experiences,  and  the  ac- 
cumulation and  elaboration  of  these  into  new  combinations  of  the 
faint  type  of  consciousness,  has  been  the  law  of  their  development. 
This  we  can  observe  in  the  education  of  one  generation  of  living 
animals,  and  it  has  doubtless  been  the  law  of  the  generations  of 
the  past  as  well.  We  may  then  review  the  probable  method  of 
development  of  mind  through  the  ages  of  past  time. 

IV.    THE    DEYELOPMENT   OF   MIND. 

In  the  first  place,  it  is  evident  that  the  evolution  of  mind  has 
been  due  to  the  activity  of  animal  life.  Although  not  asserted,  it 
is  sometimes  implied  that  '^  circumstances,"  in  which  the  animal 
is  passive,  have  been  the  efficient  cause  of  mental  development. 
That  this  could  have  been  the  case  is  inherently  impossible,  and 


446  METAPHYSICAL  EVOLUTION. 

since  animals  of  the  lowest  types  possess  powers  of  movement, 
their  activity  has  necessarily  been  an  immediate  cause,  while  sur- 
rounding circumstances  have  exercised  a  controlling  influence. 

Animal  activity  must  be  traced  to  the  generation  of  force  or 
motion  by  a  protoplasmic  body  which  is  constantly  supplied  with 
nutriment.  This  production  of  force  is  the  basis  of  the  acts  of 
animals,  up  to  and  including  man ;  often,  as  remarked  by  Prof. 
Bain,  displaying  itself  in  aimless  discharges  or  playful  movements, 
as  in  lambs  and  boys. 

But  we  observe  even  in  very  simple  organisms,  as  the  Ammla, 
etc.,  that  many  movements  are  not  aimless,  nor  without  design. 
"We  observe  that  these  mere  specks  of  jelly  devour  nutritious  sub- 
stances, and  reject  the  innutritions  ;  that  they  even  distinguish 
between  the  Diatom  which  contains  protoplasm  within  its  shell, 
and  the  empty  shell.  Many  facts  of  this  kind  lead  us  to  believe 
in  the  consciousness  of  these  pioneers  of  life,  and  seem  to  show 
that  they  have  experiences  of  the  pleasures  of  nutrition,  and  of 
the  pains  of  retaining  insoluble  substances  in  the  seats  of  assimi- 
lation. It  would  also  appear  that  they  rememler  these  sensations, 
so  as  to  seek  the  pleasures  and  reject  the  pains,  when  in  the  course 
of  their  wanderings  they  again  come  into  contact  with  the  ma- 
terial objects  which  have  caused  thenl.  Given  these  two  terms, 
sensibility  (consciousnsess)  and  memory,  and  we  have  the  con- 
ditions by  means  of  which  the  entire  complex  superstructure  of 
the  affectional  and  the  intelligent  acts  has  been  elaborated  out  of 
mere  movements. 

This  has  been  accomplished  by  the  well-known  laws  of  organi- 
zation of  habits,  and  heredity.  The  performance  of  an  act  under 
stimulus  so  modifies  the  structure  of  the  bioplasts  of  the  brain  as 
to  facilitate  its  repetition.  With  further  repetition  the  organiza- 
tion is  soon  complete,  and  action  follows  the  stimulus  without 
direction,  so  long  as  no  adverse  influence  affects  the  consciousness. 
Whether  the  act  be  one  of  the  Rational  or  Anaesthetic  orders,  from 
this  habitual  stage  it  becomes  automatic  in  the  true  sense,  between 
which  and  the  reflex  act  no  line  can  be  drawn.  It  is  evident  that 
the  degree  of  consciousness  present  in  animals  will  depend  on  the 
number  of  changes  appearing  in  their  surroundings,  whether  due 
to  modifications  of  the  external  world,  or  movements  of  their  own 
bodies.  Inasmuch  as  the  habits  of  the  lower  animals  are  few  and 
simple,  most  of  them  must  be  automatically  performed,  the  con- 
sciousness being  only  present  at  the  commencements  of  the  several 


THE   ORIGIN  OF  TOE  WILL.  447 

processes.  It  is  probable  tliat  the  organization  of  mental  functions 
was  at  the  first  identical  with  the  so-called  organic  functions,*  so 
far  as  they  consist  of  mechanical  movements  ;  and  that  the  latter 
early  became  reflex  and  devoid  of  consciousness,  developing  sub- 
sequent forms  through  mechanical  causes.  The  organization  of 
mental  functions,  on  the  other  hand,  was  by  continued  education, 
which  requires  the  presence  of  consciousness  at  every  step. 

The  well-known  fact  of  the  inheritance  of  mental  qualities 
shows  that  the  evolution  of  mind  has  advanced  by  a  continued 
process  of  accumulation  as  the  product  of  animal  experiences. 
The  new  generation  has  inherited  the  organization  of  the  old,  and 
all  the  reflex  and  automatic  activities  entailed  by  it,  and  has  pro- 
ceeded in  proportion  to  its  activity  to  acquire  new  experiences, 
habits,  and  organization. 

V.    THE   BEGII^NIXGS   OF   DEVELOPMENT. 

(a)   The  Feeliiigs. 

The  intellectual  faculties  of  every  animal  thus  belong  to  two 
classes  :  first,  those  which  have  been  inherited  ;  and  second,  those 
which  it  has  acquired  by  its  own  experiences.  Of  course  4:)rogress 
consists  in  accessions  to  the  latter  class,  since  inheritance  without 
addition  is  mere  repetition.  If  no  acquisitions  were  made,  or  to 
be  made,  the  mental,  i.  e.,  the  cerebral  organization  inherited  by 
animals  would  continually  repeat  the  form  of  their  actions  as  un- 
erringly as  the  nature  of  a  machine  gives  the  character  to  the 
movements  propagated  through  its  wheels  and  cranks.  That 
much  the  larger  proportion  of  animal  acts  are  of  this  class,  that 
is,  are  automatic,  there  can  be  no  room  to  doubt.  With  an  im- 
petus to  movement  given,  the  strongest  liking  or  disliking  selects 
the  object  or  direction,  and  the  reason  furnishes  the  mode  of  ac- 
quisition or  avoidance.  The  known  past  teaches  of  the  unknown 
future,  and  the  established  circle  of  the  functions  of  life  is  ful- 
filled.    But  without  acquisitions,  development  is  impossible. 

Acquisitions  to  experience  are  gained  by  movements  of  the 
body,  and  hence  by  the  mental  activity  to  which  the  latter  are 
due.  But  it  is  evident  that  the  primary  movement  has  preced- 
ence in  the  order  of  time  over  the  feeling  which  deflects  it,  or 
the  experience  which  directs  later  actions.     In  the  lowest  animal 

*  See  "  On  Consciousness  in  Evolution,  "  "Pcnn  Monthly,"  1875,  Aug.,  where 
this  view'  is  held. 


4^8  METAPHYSICAL  EVOLUTION. 

the  first  movement  was  doubtless  a  mere  discliarge  of  force  ;  but 
the  first  designed  action,  the  appropriation  of  food,  was  due  to  a 
sense  of  want  or  hunger,  which  is  a  form  of  pain.  This  was  fol- 
lowed by  gratification,  a  pleasure,  the  memory  of  which  consti- 
tuted a  motive  for  a  more  evidently  designed  act,  viz. :  pursuit. 

These  two  mental  states,  the  one  painful,  the  other  pleasurable, 
form  the  basis  in  the  feelings  of  all  appetent  acts.  The  painful 
sense  of  want  is  the  motive  to  the  performance  of  the  jDrimary 
class  of  actions,  and  the  experience  of  pleasurable  gratification  fur- 
nishes the  motive  for  a  class  which  must  be  regarded  as  secondary. 

The  primary  organized  feelings  of  animals  are  not  numerous. 

In  man,  the  most  highly  developed.  Prof.  Bain  enumerates  * 
only  eleven  types,  and  some  of  these  he  states  may  be  further  re- 
solved. From  the  stand-point  of  the  evolutionist  this  is  evidently 
necessary,  and  a  corresponding  reduction  in  number  can  be  made. 
The  develoiDment  of  the  feelings  has  proceeded  from  the  early  be- 
ginnings above  described,  in  subsequent  ages,  pari  passu  with  that 
of  the  intellect.  It  is  necessary  in  the  nature  of  things  that  it 
should  be  so,  since  the  finer  and  fuller  the  sensibility  to  pleasures 
and  pains  in  all  directions,  the  greater  will  be  the  complexity  of 
experience,  and  hence  of  intelligence.  It  is  not  practicable  to 
trace  the  history  of  the  feelings  here,  but  I  allude  briefly  to  one 
class  of  them — the  social  affections — as  they  have  been  treated  by 
Herbert  Spencer,  whose  contributions  to  this  department  of 
knowledge  have  been  very  important. 

This  author  maintains  that  the  social  affections  are  the  product, 
in  the  department  of  mind,  of  the  function  of  reproduction. 
They  are  the  organized  products  of  experiences  of  pleasures  de- 
rived from  fellow  beings,  just  as  other  kinds  of  likes  and  dislikes 
are  derived  from  experiences  of  the  qualities  of  various  objects. 
It  is  sufficiently  evident  that  this  faculty  must  survive,  and  the 
social  instincts  become  more  and  more  refined  or  specialized.  It 
is  a  remarkable  fact  in  the  successional  relations,  and  hence  evo- 
lution, of  the  vertehrata,  that  the  only  system  that  has  accompa- 
nied the  nervous  in  its  progress  from  generalization  to  specializa- 
tion and  perfection,  is  the  reproductive.  Man,  standing  at  the 
head  of  the  series  by  his  develojDcd  brain,  possesses  also  the  most 
specialized  reproductive  system.  He  is  inferior  to  many  other 
Mammalia  in  his  osseous  and  muscular  type,  and  in  his  digestive 

*  "  The  Emotions  and  the  Will,"  p.  36. 


THE   ORIGIN   OF   THE  WILL.  449 

organs,  including  dentition,  etc.,  but  the  orders  wliicli  are  his 
superiors  in  these  respects  yield  to  him  the  supremacy  in  the  two 
systems  mentioned. 

Functionally  the  two  systems  oppose  each  other,  and  that 
exercise  of  the  one  is  at  the  exjoense  of  the  other  is  a  physiological 
law.  Health  of  the  individual,  and  persistence  of  the  species, 
depend  on  the  maintenance  of  the  equilibrium  between  them. 
This  is  because  success  in  obtaining  food  on  the  one  hand  depends 
on  intelligence,  and  undue  power  can  not  be  expended  in  other 
directions  without  starvation.  Thus  the  law  of  evolution  lends 
full  support  to  the  doctrine  first  formulated  by  Kant,  of  the  dual 
nature  of  the  human  mind,  in  its  division  into  the  intellect  and 
the  affections. 

(b)  In  the  Intelligence. 

The  intellect  includes  a  record  of  experiences  of  resemblances 
and  differences,  of  causes  and  effects,  arranged  in  orders  of  place, 
time,  and  of  qualities  of  all  kinds.  The  importance  of  an  intellect 
depends  on  the  number  of  experiences  it  contains  ;  on  the  clear- 
ness with  which  qualities  can  be  brought  into  consciousness  ;  on 
the  correctness  with  which  the  classification  expresses  the  quali- 
ties ;  on  the  relation  which  the  qualities  preferred  bear  to  an  ob- 
ject of  pursuit ;  and  on  the  rapidity  with  which  any  or  all  of  these 
functions  may  be  performed.  The  triumph  of  reason  is  foresight 
or  predication,  in  which  it  brings  into  consciousness  the  unknown, 
by  reproducing  its  experiences  of  the  known.  This  is  the  serv- 
ice rendered  by  education,  by  the  acquisition  either  of  experiences 
themselves,  or  of  the  experiences  of  others. 

Acquisitions  then  do  not  imply  a  predication  of  the  unknown 
from  the  known,  but  an  actual  addition  to  the  stock  of  the  known. 
The  automatic  life  above  described  includes  no  such  process,  but 
is  a  routine  varying  only  in  unimportant  details,  and  changing  in 
no  great  feature.  Progress  evidently  depends  on  something  be- 
sides knowledge,  for  in  proportion  to  the  degree  of  progress  is  the 
departure  from  the  known,  and  in  proportion  to  the  novelty  of  a 
situation  is  experience  worthless  as  a  guide. 

Designed  actions  which  are  performed  without  a  basis  of  knowl- 
edge which  is  sufficient  for  predication  are  not  automatic.  That 
is,  while  the  activity  may  be  physically  spontaneous  and  comi)ul- 
3ory,  the  direction  it  takes  and  the  mode  of  its  execution  can  not 
be  automatic,  unless  the  machinery  which  must  give  the  direction, 
and  which  creates  the  mode,  be  already  in  existence. 
29 


450  METAPHYSICAL  EVOLUTION. 

The  field  of  the  known  is  very  limited,  as  compared  with  that 
of  the  unknown,  in  the  experience  of  the  Amcela.  In  its  first 
movements,  it  has  absolutely  no  basis  on  which  to  establish  an 
anticipation  of  the  future.  Such  is  also  the  situation  of  the  young 
of  every  animal.  But  the  cases  of  the  inferior  and  superior  spe- 
cies present  the  important  difference  that  in  the  former  there 
exist  few  or  no  mental  powers  derived  by  inheritance,  while  in 
the  latter  such  are  present  in  proportion  to  the  position  of  the 
species  in  the  scale  of  intelligence. 

The  facts  of  evolution  teach  that  the  habits  of  animals  have 
been  modified  during  past  geological  ages,  under  the  influence  of 
changes  in  their  physical  surroundings.  While  these  changes  may, 
perhaps,  have  furnished  the  stimuli  to  the  adoption  of  new  habits, 
the  conditions  have  not  often  been  so  rigid  as  to  define  exactly 
what  those  habits  should  be,  in  some  or  all  of  their  details.  The 
animal  has  necessarily  proceeded  blindly  in  many  instances ;  in 
others,  his  mental  darkness  has  been  illumined  by  a  low  grade  of 
imagination.  This  may  be  believed  in  view  of  the  many  attempts 
which  animals  often  make  before  succeeding  in  attaining  a  desired 
end.  Imagination  plays  an  important  part  in  the  origin  of  mo- 
tives and  of  actions,  and  is  related  to  predication.  It  is  defined 
as  the  presentation  or  construction  of  images  or  representations 
from  items  of  experience,  which  representations  so  far  differ  in 
the  connection  of  their  details  from  actual  experience,  or  so  far 
lack  the  qualities  of  experiences,  as  not  to  constitute  a  predica- 
tion of  future  events.  Predication  mav  be  defined  as  the  certain 
knowledge  of  the  unexperienced  from  the  experienced  ;  while 
imagination  includes  the  grades  of  probable,  possible,  and  impos- 
sible concepts,  constructed  from  the  same  material  as  predication. 
Whether  this  faculty  exists  in  the  animals  which  can  not  speak, 
is  not  readily  ascertained  ;  but,  inasmuch  as  many  of  them  predi- 
cate, it  is  probable  that  they  possess  some  degree  of  imagination 
also.  But  it  is  obviously  a  quality  of  the  highest  types  of  mind, 
since  its  development  depends  primarily  on  the  furniture  of  mem- 
ory, derived  from  a  long  period  of  experience,  whose  amount  de- 
pends on  receptivity  and  retentiveness. 

YI.    THE   OEIGIi^   OF   MOTIVES. 

It  has  been  said  that  the  operation  ordinarily  called  choosing, 
in  which  the  will  is  popularly  supposed  to  be  free,  consists  merely 
of  a  sum  in  addition  and  subtraction,  where  various  inducements 


THE   OPJGIX   OF  THE  WILL.  451 

are  balanced,  the  resultant  preponderance  being  expressed  in  the 
act.  It  will  be  easily  seen  that  while  this  statement  is  true  in  re- 
gard to  cases  where  the  elements  of  the  calculation  are  known,  it  is 
not  true  where  any  or  all  of  them  are  unknown.  The  difference 
in  the  two  cases  is  very  great.  All  likes  and  dislikes  are  based 
upon  experience  or  knowledge ;  and  when  there  is  no  knowledge, 
likes  and  dislikes  can  not  be  said  to  exist.  Since  likes  and  dis- 
likes constitute  motives,  where  the  former  are  wanting  the  latter 
are  also  wanting.  Whatever  inducements  are  presented  from  be- 
yond the  field  of  knowledge  are  derived  from  the  imagination, 
and  are  in  self-conscious  minds  relatively  weak  as  motives,  or 
absolutely  without  weight.  They  might  be  regarded  as  motives 
in  embryo,  ready  to  become  such  on  the  acquisition  of  a  corre- 
sponding experience.  The  imagination  can  prefigure  one  alterna- 
tive as  well  as  another,  in  a  direction  wdiere  experience  is  wanting, 
and  might  indeed  be  said  under  such  circumstances  to  have  no 
existence,  and  the  expression,  ^'1  can't  imagine,"  be  thought  to 
have  foundation  in  fact.  The  influence  of  such  a  guide  is  not 
imperative,  and  raises  no  obstacle  to  the  origin  of  a  new  feature 
of  consciousness  by  an  act  of  choosing,  when  the  pressure  to  act 
at  all  is  sufficiently  great. 

There  is,  perhaps,  but  one  situation  of  the  mind  where  the 
pressure  of  feeling  is  strong  enough,  and  predication  and  imagina- 
tion sufficiently  excluded,  to  develop  a  will  which  shall  create 
motives  rather  than  obey  them.  This  is  in  the  cases  where  self- 
interest  is  weighed  in  the  balance  against  the  interest  or  good  of 
other  people.  Here  the  feelings  are  most  severely  ju-essed,  and 
the  future  results  to  self  most  uncertain.  Self-sacrifice  may  be 
beneficial  to  self,  or  it  may  not :  one  may  be  the  gainer  by  the 
general  prosperity,  or  he  may  be  the  loser.  Morality  may  promise 
future  good  to  the  community,  but  why  sacrifice  self  for  the  com- 
munity ?  Gratitude  for  services  rendered  is  an  uncertain  antici- 
pation. Man's  most  limited  knowledge  and  greatest  inability  in 
predication  is  in  the  field  of  human  motives  and  actions,  and 
chiefly  in  respect  to  those  which  belong  to  his  moral  feelings.  As 
already  remarked,  the  complication  in  this  direction  is  so  great  as 
to  produce  the  effect  of  novelty  :  so  that  man,  come  into  posses- 
sion of  an  intellect  which  is  the  product  of  ages  of  development, 
finds  before  him  a  new  field  of  his  own  making,  where  his  in- 
herited powers  fail. 

This  is  the  field  where  the  most  momentous  decisions  possible 


452  METAPHYSICAL  EVOLUTION". 

in  human  life  are  made.  Since  questions  of  right  and  wrong  re- 
late to  the  happiness  of  men  in  their  relations  to  each  other,  the 
social  affections  are  the  stronghold  of  the  motives  that  bear  on 
this  result.  It  is  evident  that  a  thousand  subordinate  motives 
take  their  direction  from  the  primary  decisions  between  these  two 
original  alternatives  of  feeling. 

It  is  true  that  the  predication  of  human  actions,  necessitated 
by  bodily  functions  alone,  is  eas}^  even  when'  they  come  to  be  of 
a  highly  complex  character,  as  in  the  mercantile  transaction  of  a 
populous  business  center.  But  so  soon  as  the  ethical  element 
enters  into  the  calculation  the  difficulty  is  greatly  increased,  and 
with  the  majority  of  men  predication  ceases,  and  faith  begins. 
This  is  illustrated  in  the  many  credit  transactions,  without  which 
it  is  well  known  that  trade  on  any  but  the  most  limited  scale  is 
impossible.  So  it  must  be  admitted  that  many  men  practice  faith 
in  many  affairs,  and  that  this  faith  is  chiefly  reposed  in  the  moral 
excellence  of  other  men.  Under  these  circumstances,  that  state  of 
the  affections  arises  in  most  men  which  is  termed  faith,  and  which 
is  only  present  in  the  highest  form  of  progressive  action,  whether 
the  results  of  tliat  action  be  beneficial  or  not.  It  is  a  condition  of 
the  affections,  as  imagination  is  a  condition  of  the  intellect.  The 
lowest  animal,  when  attempting  a  novel  act  in  obedience  to  im- 
perative stimuli,  doubtless  moves  blindly,  and  adopts  one  of  two 
or  more  alternatives  through  pure  accident.  In  animals  of  a 
higher  grade  of  intelligence,  new  situations  are  known  to  be  such, 
and  fear  or  suspicion  is  the  usual  result.  Generall}^,  animals  of  the 
higher  orders  do  not  adopt  new  habits  excepting  under  severe  press- 
ure, and  the  majority  of  them  have  perished,  in  past  geologic  ages, 
on  account  of  their  inability  to  assume  new  modes  of  life.  Never- 
theless, in  so  far  as  an  animal  or  a  man  ventures  into  an  unknown 
field  of  action,  where  he  is  without  the  guidance  of  a  past  ex- 
perience, he  or  it  performs  an  act  of  trust  in  the  broad  meaning 
of  the  word.  So  far  as  this  state  of  mind  is  known  to  the  subject, 
the  act  is  one  of  true  faith  in  the  restricted  or  proper  sense  of  the 
word.  Imaginations  may  and  do  assume  to  men  the  importance  of 
truths,  and  in  so  far  they  are  such  to  them.  But  in  proportion 
as  this  is  the  case,  faith  in  its  proper  sense  is  wanting,  and  the 
action  following  is  automatic.  The  highest  form  of  intellect  is 
necessary  to  the  highest  form  of  faith,  since  it  is  only  by  a  knowl- 
edge of  the  absence  of  knowledge  that  an  act  of  faith  is  possible. 
In  proportion  to  this  knowledge  of  self  is  faith  enlarged  ;  in  pro- 


THE   ORIGIN   OF   THE   WILL.  453 

portion  to  certainty,  or  supposed  certainty,  in  affairs,  is  faith 
diminished  in  its  scope. 

It  is  evident  then  that,  abstractly  speaking,  occasions  must 
arise  in  human  experience  where  a  decision  between  two  alterna- 
tives is  dependent  on  choice  alone.  That  these  occasions  have 
arisen,  and  the  choice  been  made,  is  shown  by  the  existence  of  the 
altruistic  class  of  actions.  The  number  of  these  occasions  may 
not  be  very  great,  but  the  consequences  are  ver}'  important.  In 
whatever  direction  these  decisions  are  made,  long  series  of  auto- 
matic actions  are  organized. 

Although  the  existence  of  the  altruistic  class  of  acts  affords  the 
clearest  proof  of  the  origin  of  will,  it  is  not  denied  that  corre- 
sponding situations  may  not  occur  in  other  directions.  It  is  also 
probable  that  will,  once  organized  as  a  faculty  of  consciouness, 
can  be  exercised  in  many  acts  in  opposition  to  habits,  differing  in 
accordance  with  the  constitution  of  the  individual ;  and  that  it 
can  be  inherited  like  any  other  quality  of  mind.  But  I  will  show 
later,  that  the  organization  of  altruistic  habits  has  narrower  limits 
than  that  of  those  of  the  appetent  class,  because  self-preservation 
depends  on  the  latter,  and  not  on  the  former,  so  that  the  appe- 
tent qualities  are  more  certain  to  be  inherited  and  survive. 

The  conclusion  of  this  portion  of  the  subject  is,  that  that  de- 
partment of  mind  called  the  feelings  *  is  the  primary  source  of 
action  ;  that  they  act  automatically,  with  or  without  the  aid  of  the 
reasoning  powers,  when  dealing  with  the  known  ;  but  when  deal- 
ing with  the  unknown  may  develop,  in  self-conscious  beings,  the 
state  of  faith  and  acts  of  will ;  that  this  freedom  is  born  of  ten- 
sion of  the  affections  and  of  inability  of  the  intellect. 

Thus  have  the  irregular  and  fortuitous  decisions  of  animals 
been  replaced  by  volition,  as  the  highest  quality  of  the  mind,  and 
therefore  the  crown  of  evolution.  No  new  "  physical ''  force  is 
here  called  into  requisition.  The  determination  of  the  direction 
of  such  forces  already  existing  in  or  passing  through  the  brain  in 
executive  action  need  not  add  to  nor  substract  from  them.  Will  is, 
under  these  circumstances,  looked  upon  as  developed  consciousness. 

All  this  is,  of  course,  opposed  by  the  doctrine  of  the  origin  of 
moral  excellence  by  development,  on  the  basis  of  the  utilitarian 
theory  of  morals.  I  therefore  proceed  to  a  brief  examination  of 
its  claims  in  this  direction. 

*  Which  appears  to  be  identical  with  what  Schopenhauer  calls  the  will. 


4:54:  METAPHYSICAL  EVOLUTION". 

Good  is  well  defined  as  tlie  greatest  happiness  of  the  greatest 
number  ;  and  by  a  natural  transfer,  the  term  is  applied  to  what- 
ever is  conducive  to  that  object.  It  therefore  includes  not  only 
present  pleasures,  but  also  the  influences  which  conduce  to  future 
pleasures,  and  which  may  be  sown  in  the  mind  long  before  they 
bring  forth  fruit.  As  present  pleasures  are  not  always  consistent 
with  greater  ones  in  the  future,  so  present  pleasure  is  not  always 
good.  Evil  being  the  reverse  or  negation  of  good,  or  happiness,  is 
avoided  by  all  beings  to  whom  it  is  consciously  known  ;  but  what 
they  regard  as  evil  will  of  course  depend  on  their  intelligence  in 
determining  or  predicating  the  future  effects  of  actions.  But  no 
matter  what  the  degree  of  intelligence,  no  responsibility,  as  usu- 
ally understood,  can  be  expected  of  beings  which  have  no  power 
of  choosing,  or  will. 

The  utilitarian  theory  of  the  evolution  of  morals  asserts  that 
the  development  of  goodness  is  simply  due  to  the  discovery  and 
enforcement  of  the  law  of  self-jirotection  and  preservation.  The 
selfish  interests  require  the  protection  of  person  and  property, 
without  which  a  community  is  an  impossibility.  Law  being  thus 
established  and  enforced,  moral  habits  are  imposed  ujDon  men, 
which  become  incorporated  into  character  and  transmitted  to  suc- 
ceeding generations.  This  is  all  doubtless  true,  but  whether  it  is 
a  fundamental  or  secondary  truth  is  the  point  requiring  attention. 

The  fundamental  objection  to  this  hypothesis  is,  that  the  al- 
truistic affections  are  not  inherited  or  transmitted.  This  is  be- 
cause the  pains  and  penalties  of  wrong-doing  as  inflicted  by  law, 
can  not  (and  ought  not  to)  overcome  the  inherent  instinct  of  self- 
preservation  in  man.  It  is  true  that  moral  character  is  inherited, 
and  that  changes  in  this  department  for  better  or  worse  are  trans- 
mitted to  offspring.  The  mental  organization  of  a  race  may  be 
improved  by  the  weakening  of  the  emotional  or  the  strengthen- 
ing of  the  rational  faculties.  But  since  the  affections  are  at  the 
foundation  of  all  activity  whatsoever,  of  right-doing  as  well  as  of 
wrong-doing,  it  is  obvious  that  no  amount  of  legal  restraint  can 
render  them  innocuous.  Their  existence  is  necessary  for  self- 
preservation,  and  law  only  restrains  their  activities  to  certain  di- 
rections. That  intelligence  tends  to  restrain  wrong-doing  is  true  ; 
but  although  intellect  is  inherited,  the  manner  in  which  its  teacli- 
ings  are  applied  in  practice  is  not.  Each  man  must  learn  the 
merits  of  different  courses  of  action  in  regard  to  morals  for  him- 
self ;  his  intelligence  places  before  him  the  facts,  and  shows  him 


THE   ORIGIN  OF  TUE   WILL.  455 

how  to  execute  his  wishes,  but  the  state  of  his  affections  deter- 
mines the  direction  of  his  acts.  Moral  amelioration  has  attended 
the  progress  of  intelligence  on  the  one  hand,  and  moral  abase- 
ment on  the  other.  Intelligence  is  the  condition  of  the  perception 
of  moral  truth  ;  in  other  words,  intelligence,  as  applied  to  moral 
questions,  is  the  conscience.  Consequences  of  acts  are  understood, 
and  their  relations  to  the  pleasures  and  pains  of  men  are  weighed. 
Thus,  no  doubt,  the  world  has  advanced  in  the  knowledge  of  good 
and  evil,  and  of  right  and  wrong.  That  it  has  improved  in  the 
practice  of  right  has  not  been  due  to  the  inheritance  of  respect 
for  law,  but  to  the  self-destructive  nature  of  wrong.  That  con- 
tinued wrong  sooner  or  later  ends  in  the  destruction  of  the  wronc:- 
doer,  either  from  within  or  without,  must  be  generally  admitted. 
Thus  is  the  truth  of  the  doctrine  of  '^  the  survival  of  the  fittest " 
vindicated  in  moral  as  in  natural  law.  But  it  is  also  true  that 
this  law  is  restrictive  onl}^,  and  that  the  school  of  Hume  and 
Bentham  has  overlooked  the  deeper  originative  law  in  moral  phi- 
losophy, as  the  school  of  Darwin  has  done  in  biological  philosophy. 

It  may  still  be  urged  that,  if  it  be  granted  that  experience  of 
the  pains  of  evil-doing  be  not  transmitted  as  an  intellectual  ac- 
quisition from  generation  to  generation,  nevertheless  such  experi- 
ence is  sufficient  to  educate  each  separate  generation  as  it  passes, 
without  any  other  than  automatic  action  on  their  part.  It  may 
be  replied  to  this  that  the  results  thus  obtained  are  not  due  to 
will,  but  simply  follow  compulsion,  the  motive  thus  created  only 
varying  in  strength  with  the  characters  of  the  individuals.  Its 
success  is  restricted  to  circumstances  where  the  j^enalties  are  suffi- 
ciently certain  to  constitute  counter-inducements  to  effect  the 
necessary  restraint.  This  can  only  be  the  case  with  the  weaker 
members  of  society.  Wherever  there  is  sufficient  power  to  escape 
penalties,  wrong-doing  has  no  restraint.  Under  such  a  system 
might  and  right  are  identical ;  for  the  strongest  needs  no  protec- 
tion of  law.  It  is  true  that  society  can  combine  against  a  single 
malefactor,  but  it  is  also  true  that  malefactors  can  combine.  In 
fact,  it  is  one  of  the  usual  phenomena  of  human  society  to  find 
men  becoming  malefactors  as  soon  as  they  attain  to  power ;  or  to 
find  society  governed  by  a  few  malefactors  who  have  an  army  to 
enforce  their  pleasure. 

While  then  inheritance  does  not  secure  the  performance  of 
altruistic  acts,  appetent  affections  maybe  so  increased  by  accumu- 
lation in  descent  as  to  become  uncontrollable,  so  that  will  either 


456  METAPHYSICAL  EVOLUTIOK 

does  not  come  into  existence,  or  is  extinguished,  so  far  as  regards 
those  affections.  In  such  a  situation  there  is  no  such  equivalency 
between  opposing  motives  as  gives  opportunity  for  the  will,  the 
experience  of  appetent  pleasure  being  too  strong  to  allow  of  hesi- 
tancy in  the  face  of  vague  representations  of  imaginary  conse- 
quences on  the  other  side.  Even  in  highly  intelligent  men,  to 
whom  consequences  are  best  known,  knowledge  may  be  thrust 
from  consciousness,  by  strong  feeling  in  favor  of  one  alternative 
at  the  moment  of  action. 

YII.    COl^SEQUEIirCES. 

It  is  now  w^ell  to  consider  how  far  an  automatic  mind  has  any 
claim  to  personality  or  individuality,  as  generally  understood. 
From  the  usual  stand-point,  a  being  without  'liberty,"  or  will 
properly  so  called,  is  without  character,  and  is  in  so  far  a  nonen- 
tity. Even  the  character  of  the  Deity  can  not  escape  this  de- 
structive analysis ;  for  according  to  Spinoza,  if  He  is  good,  but  a 
single  line  of  action,  without  alternatives,  lies  open  to  God,  if  He 
be  at  the  same  time  omniscient.  All  this  is  changed  if  the  ele- 
ment of  spontaneity  in  character  be  presupposed.  The  existence 
of  such  a  quality  in  man  renders  foresight  of  its  decisions  in  some 
cases  no  more  than  a  calculation  of  chances,  and  in  other  cases 
impossible  ;  thus  offering  the  only  conceivable  limit  to  omnis- 
cience, and  hence  to  omnipotence.  And  as  we  regard  the  good- 
ness of  God  as  the  anchor  of  the  universe,  if  that  goodness  be  in 
some  respect  inconsistent  with  omnipotence,  we  are  strengthened 
if  we  discover  that  there  is  ground  for  correcting  our  traditional 
suppositions  in  regard  to  the  latter.  Can  we  not  find  this  ground 
in  a  liberty  or  freedom  which  is  the  condition  of  what  we  suppose, 
in  the  absence  of  knowledge,  to  be  the  characteristic  of  the  highest 
class  of  conscious  existences  ? 

Note. — Another  explanation  of  this  conclusion  of  Spinoza's,  quite  apart  from 
the  question  of  human  freedom,  is  to  be  found  in  some  of  the  necessary  properties 
of  matter.  The  old  theologians  expressed  this  point  obscurely  in  their  phrase,  "  the 
intractability  of  matter."     (Ed.  1886.) 

Second  Note.  (Ed.  1886.) — The  preceding  essay  was  written  several  years 
prior  to  that  on  Catagenesis.  In  the  latter  article  a  mental  quality  was  referred  to 
as  present  in  all  animals,  which  constitutes  "  the  will  "  of  various  writers,  although 
it  is  not  free.  It  is  described  in  the  following  passage  :  "  Why,  from  a  purely  me- 
chanical point  of  view,  is  the  adductor  muscle  of  the  right  side  of  the  horse's  tail  con- 
tracted to  brush  away  the  stinging  fly  from  the  right  side  of  the  horse's  body,  rather 
than  the  left  adductor  muscle  ?    Why  was  the  contraction-provoking  energy  deflected 


ON   THE   ORIGIN   OF  THE  WILL.  457 

into  the  right  interspinal  motor  nerves  rather  than  into  those  of  the  left  side  ?  " 
The  conclusion  was  that  this  phenomenon  can  not  be  explained  on  purely  mechani- 
cal principles  ;  but  that  it  required  the  assumption  of  the  thesis  that  "  energy  can 
be  conscious."     {Supra,  p.  427.) 

Further  thought  on  this  subject  shows  clearly  that  this  conscious  state  of  energy 
is  self-directive  in  accordance  with  the  lessons  of  experience,  but  without  being 
necessarily  free  in  the  sense  referred  to  in  the  preceding  essay.  In  Mammalia  the 
current  of  energy  derived  from  stimulus,  after  reaching  the  cortical  cells  of  the  an- 
terior cerebral  lobes,  issues  from  them  in  a  direction  appropriate  to  the  needs  of 
the  animal,  having  undergone  a  deflection  or  determination  within  them.  This 
capacity  for  "  design  "  is  peculiar  to  beings  which  can  be  conscious,  and  constitutes 
the  most  important  proof  in  evidence  of  a  degree  of  control  of  mind  over  matter. 
The  evidence  strongly  suggests  that  this  control  is  greatest  when  the  environment 
is  simple  or  generalized,  since  motives  are  then  relatively  simple. 

Note  to  Catagenesis  by  the  Author,  1886.  On  p.  434  reference  is  made  to 
the  fact  that  "  in  chemical  reaction  the  preference  of  energy  is  to  create  solid  pre- 
cipitates." This  fact  is  but  one  illustration  of  the  law  of  thermo-chemistry  that 
*'  in  any  reaction,  those  bodies,  the  formation  of  which  gives  rise  to  the  greatest  de- 
velopment of  heat,  are  formed  in  preference  to  others."  This  is  a  retrograde  meta- 
morphosis of  energy,  or  catagenesis. 


IS"DEX. 


Acceleration,  vi,  142,  182,  287,  383. 

Acceleration  and  retardation,  2,  11,  125, 
127,  297. 

Acrania,  322,  323. 

Actinia,  33, 

Actinophrys,  27,  187,  192. 

Actinopteri,  325,  326. 

^sthetophore,  419. 

Aethalium,  396. 

Agassiz,vii,  8,  45,  58,  60,  61,  62,  83,  91, 
92,  103,  121,  124. 

Ageniosus,  327. 

Allen's  "Anatomy,"  272,  279. 

Allen,  H.,  115,  242. 

Allen,  Keen,  and  Pepper  on  "  Universal 
Hyperostosis,"  183. 

Allman,  Prof.,  415, 

Altruism,  xi,  237,  441,  453. 

Amhlydomis  sinosus,  375. 

Amblyopsis,  196. 

Amblypoda,  278,  342,  343,  344,  346,  348, 
360,  368,  371,  374, 

Amblystoma,  4. 

Amblijstoma  mavortium^  88. 
tigrhmm,  89. 

Ameiva  pleii,  87. 

American  Association  for  the  Advance- 
ment of  Science,  x,  xi,  xii,  xiii. 

"American  Naturalist,"  ix,  xi,  xii,  xiii, 
244,  277,  359,  363,  383. 

Ametabola,  316. 

Aniiui'us,  4. 

Amiurus  albidics,  85. 
lynx,  85. 

Ammocoetes,  316. 

Ammonites,  18. 


Amoeba,  440,  445,  446,  450. 
Amoebodonts,  247,  248,  257. 
Araphioxus,  182. 
Amphiuma,  333. 
Anaptomorphus  cemiilus,  279. 

homnnculus^  279. 
Ancestral  types  of  mammalia  cducabilia, 

266. 
Anchitherium  awclianense,  275. 
Ancisfrodon  cordortrix,  197. 

piscivorus,  197. 
Anelytropidae,  337. 
Anguidae,  337. 
Aniellidae,  337. 
Anisonchus,  245,  359. 
Anolis,  4. 

Anoplotberium,  247,  265,  370. 
Anthracotherium,  x. 
Anthropoidea,  342,  343. 
Antiarcha,  323. 
Antilocapra,  383. 
Antiodonts,  247. 
Anura,  331,  332,  333. 
Aphelops  meffalodvs,  369. 
Aphododiridae,  328. 
Appendicularia,  322. 
Archcelu7'us  dibilis,  375. 
Archaesthetism,  xii,  406,  414,  419,  421. 
Arcliaeopteryx,  340. 
Arcifcrous  anura,  95,  218. 
Artiodactyla,    344,    368,   371-374,    375, 
399,  401. 
omnivora,  199. 
Ascertained  cases  of  transition,  87. 
Ascidia,  399. 
Atrophy,  13,  127. 


4:60 


INDEX. 


Aturia,  lY. 

Australian  native,  291. 
Avian  line,  the,  340. 

Bain,  Prof.,  446,  448. 

Baird,  S.  R,  55,  85,  87. 

Barnard,  205. 

Bascanium  constrictor,  197. 

Bathmism,  26,  205,  226,  414. 

Bathmodonts,  248,  259. 

Batrachia,  351. 

Batrachia  anura,  46,  216,  332. 

Beginnings  of  development,  the,  447. 

Bennett,  Alfred,  199,  214. 

Bentham,  455. 

Bokorny,  430. 

Borborocoetes,  4. 

Bos,  348. 

Bothriolepis  canadensis,  323. 

Boulanger,  337. 

Bibron,  95. 

Bidens  frondosa,  86. 

BischofP,  290. 

Brachiopoda,  399. 

Branchiostoma,  322,  384. 

Bridger  fauna,  302. 

Broca,  290. 

Bronn,  Prof.,  45,  51,  102. 

Bufoniformia,  217. 

Bunodont  type,  243. 

Bunotheria,  343,  346,  349. 

Buteo,  4. 

Calamodon,  278. 

California  Academy  of  Sciences,  xi. 

Caraelidae,  375. 

Canidae,  246. 

Cams  familia.i'is,  224. 

Caprimulgidae,  341. 

Cariacus  virginianus,  50,  177-178, 

macrotis,  178. 
Carnassial  bunodonts,  the,  251. 
Carnivora,  264,  278,  344-346,  348,  399- 

.401. 
Carpenter,  Dr.,  viii,  191,  206,  438. 
Casts  of  brain-chambers  of  extinct  mam- 
malia, figures  of,  308. 
Catagenesis,  xiii,  422,  428,  434. 


Caudisona,  4. 
Causes  of  evolution,  14. 
Cebidae,  180. 
Cebus  apella,  12. 

capucinus,  12,  38. 
Celestics  pJioxinus,  84. 
Cell-repetition,  on,  185. 
Centetes,  360. 
Centetidas,  348. 
Centrotelma  geograpldcum,  85. 
Cephalizatiou,  39. 
Cervidae,  177. 

Cetacea,  26,  342,  343,  347,  349,  399. 
Chaenobryttus  viridis,  213. 
ChEetodontidas,  330. 
Chamcesaura  angiiina,  84. 
Change  in  amount  of  growth-force,  200. 
Characinidae,  327. 

Character  of  higher  groups,  of  the,  132. 
Chelyosoma  maclovianum,  323. 
Chiromys,  180,  202. 
Chiroptera,  342,  343,  344. 
Chorophilus,  4. 
Chrondrostei,  325,  326. 
Cinclidium  maximum,  85. 
Cladodonts,  325. 
Clark,  H.  J.,  167. 
Clepsydrops,  363. 
Clevenger,  424. 
Clifford,  Prof.,  425. 
Coelenterata,  182,  413. 
Coenogenesis,  126. 
Cohnheim,  195,  406. 
Coleoptera,  316. 
Colocephali,  327. 

Comparison  of  the  opposing  series,  250. 
Complementary   diminution    of    growth 

force,  viii. 
Condylarthra,  xiii,  342-6. 
Consciousness,  energy,  and  matter,  425. 
Consciousness  in  evolution,  x,  xii,  390. 
Coranus  suhapterus,  89. 
Coreopsis  discoidca,  86. 
Correlation  of  physical  and  vital  forces, 

191. 
Corvus,  4. 
Coryphodon,  270,  272,  273,  274,  276,  369, 

374. 


INDEX. 


4G1 


Coryphodon  elephantopiis^  2G9. 
Coryphodontidae,  359. 
Cosoryx,  224,  271,  376. 
Crania  of  anura,  222. 
Craniata,  322,  323. 
Creodonta,  359,  365. 
Cretaceous  fauna,  302. 
Crossopterygia,  325,  326. 
Crotalus  conjluentus^  212. 
Cuvier,  8,  88,  124,  129,  146,  176 
Cyclopterus,  331. 
Cyprinidse,  327. 

Dana,  J.  D.,  39,  429. 

Darwin,  Charles,  2,  3,  11, 13, 15,  42,  106, 

124,  174,  405,  409,  455. 
Daubentonioidea,  342. 
Deltatherium  ftmdaminis,  362. 
De  Serres,  Prof.,  74,  77. 
Desmognatlms  jusca,  87. 

nigra,  87. 
Deuterosaurus,  363. 
Development  of  the  fine  arts,  153. 

of  intelligence,  149. 

of  mind,  the,  445. 
Developmental    relation   of    generic   to 

specific  characters,  82. 
Developmental    significance    of    human 

physiognomy,  281. 
Diadectidae,  335. 
Dibamid^,  337. 
Didonius  mirabilis,  338,  339. 
Didelphys,  360. 
Didymictis  protemcs,  215. 
Dimorphodon,  335. 
Dinidis  cydops,  366. 
Dinocerata,  359. 
Dinosauria,  333,  335,  336,  338. 
Dinotherium,  248. 
Diplarthra,  342,  343,  346,  347. 
Diploglossus  monotropis,  84. 
Dipnoi,  184,  324. 
Diptera,  316. 

Direction  of  repetition,  on  the,  192. 
Doctrine  of  the  unspecialized,  the,  398. 
Dohrn,  316,  317. 
D'Orbigny,  101. 
Dorypterus,  327. 


Dualism,  421, 

Dubois-Raymond,  Prof.  E,,  409. 
Dumeril,  88,  89,  91,  95. 
Dyer,  213. 
Dysodus,  349. 

Edentata,  342,  343,  344,  349. 

Effect  of  impacts  and  strains  on  the  feet 

of  mammalia,  on  the,  xii,  373. 
Effort,  195,  206-7,  426. 
Elaps,  4. 

Elasmobranchii,  319,  320,  324. 
Electric  energy,  435. 
Elements  of  mind,  the,  443. 
Elephas,  377. 

africanus,  110. 

antiqxius,  110. 

meridionalis,  110. 

planifrons,  110. 

primigenius,  110. 
Embolomeri,  331,  332. 
Embryology,  383. 
Emotions,  158,  163,  381,  447. 
Empidonax,  4. 

"  Encyclopaedia  of  Dentistry,"  104. 
Endlich,  286. 
Entocondm  mirabilis,  401. 
"  Entwickelungsgeschichte  der  Natter," 

94. 
Eobasileus,  250. 
Epochal  relations,  112. 
Epilasmia,  330. 
Equidae,  411. 
Equus,  276,  348. 
Eryops  megacephalus,  304. 
Esequibo  Indian  women,  286. 
Eucnemis  hicolor,  114. 
Eurypharyngida%  328,  329. 
Eurytherium,  370. 
Eutaenia,  4. 

Evidence  from  archaeology,  150. 
Evidences  of  derivation,  130,  215. 
Evidence  for  evolution  in  the  history  of 

extinct  mammalia,  xii,  294. 
Evolution  and  its  consequences,  ix,  1. 
Evolution  of  organisms,  the,  422. 
Evolution  of  the  vertcbrata,  progressive 
and  retrogressive,  xiii,  314. 


462 


INDEX. 


Evolutionary  significance  of  human  char- 
acter, xii,  378. 

Exact  parallelism,  vi,  46,  76,  139. 

Extent  of  parallelism,  74. 

Extinction  of  evil,  the,  169. 

"  Extinct  Mammalia  of  Dakota  and  Ne- 
braska," 384. 

Falco,  4, 

Falconer,  55,  109. 

Feelings,  the,  447. 

Felidfe,  349,  363,  366. 

Felis,  363. 

"  Final  Reports  of  the  U.  S.  Geological 

Surveys,"  v. 
Flower,  W.  H.,  104. 

Ganocephala,  332. 

Garman,  325. 

Gastrsea  theory,  219. 

Gaudry,  A.,  275. 

Gecconidge,  336. 

Gegenbaur,  322. 

General  evolution,  1. 

"  Geological  Survey  of  Montana,"  258, 

267. 
Geothlypis  teplirocotis,  85. 
Gill,  T.,  329. 
Goethe,  7. 
Goniatites,  18. 
Grade  characteristics,  viii. 
Grade  influence,  viii,  203-6. 
Gratiolet,  104. 
Gray,  86,  176. 
Gray,  Asa,  208. 
Greatest  resistance,  30. 
Gronias  nigrilahris,  84. 
Growth-force,  18,  190,  396. 
GUnther,  58,  86,  340. 
Gymnophiona,  331. 
Glyptostrobus  europcciis,  86. 

Haeckel,  ix,  x,  xiii,  75,  125,  190,  219 

229,  415. 
Halohates  amcricanus,  90. 
Haplodont  type,  243. 
Hartshorne,  Prof.,  397. 
Hayden,  F.  V.,  v,  246,  269,  369-71,  376. 


Hemibranchi,  328. 

Henry,  Prof.  Joseph,  19,  191. 

HesperornithidaB,  340. 

Hetcrodon  nasicus,  212. 

Heterology,  96. 

Heterosomata,  328. 

Hippocampidae,  328. 

Hippodonts,  249. 

Hippopotamus,  272. 

Hippotherium,  202,  411. 

JIippothe7'ium  gracile,  275. 

History  of  creation,  xiii. 

Hogg,  89. 

Holoccphali,  324. 

Holothurida,  193,  399. 

Hominidae,  180. 

Homo  sapiens,  272,  279. 

Homologies  and  origin  of  the  types  of 

molar  teeth  of  the  mammalia  educa- 

bilia,  241. 
Homologous  groups,  vi,  26,  95. 
Homology,  6. 
Humboldt,  425. 
Hume,  455. 

Huxley,  15,  136,  146,  265. 
Hyaenidae,  246,  349. 
Hyaenodon,  366. 
Hycenodon  horridus,  364. 
Hyaenodontidae,  246. 
Hyatt,  A.,  2,  8,  11,  oi,  91,  125,  408-9, 

424. 
Hyla,  4. 

Hylorana  erythrcna,  114. 
Hyopomata,  318,324. 
Hypothesis   of  evolution,  physical   and 

metaphysical,  vii,  xii,  128,  167,  287. 
Hypothesis  of  use  and  effort,  the,  403. 
Hypsilepis  analostanus,  213. 
Hymenoptera,  316. 
Hyrachyus,  247. 

Hyracoidea,  342,  343,  344,  346,  347. 
Hyracodonts,  249. 
Hyracotherium,  301. 
Hyracotherium  vcniicohon,  271. 
Hyrax,  233. 

Ichthyopterygia,  184,  333,  336. 
Ichthyornithidae,  340. 


INDEX. 


4G3 


Ichthyosaurus,  184,  336. 

Icichthys,  331. 

Icosteus,  331. 

Improvement  in  architecture,  151. 

Improvement  in  the  use  of  materials,  150. 

Increase  of  growth-force,  200-1. 

Indo-European,  2SS. 

Induction,  6,  14. 

Inexact  parallelism,  52,  139. 

Influence  of  physical  causes,  196. 

Insectivora,  347. 

Intelligence,  449. 

Intelligent  selection,  viii,  ix,  35,  208. 

Isospondyli,  327. 

Jena,  8. 

John  Day  river  epoch,  366, 
Jones,  Rupert,  86, 
Jordan,  D.  S.,  326. 

Kant,  307,  449. 
Kiowa  Indian,  288. 
Kner,  R.,  113. 
Kolliker,  15,  103. 
Kowalevsky,  x,  318. 

Laccrtilia,  334,  335,  336. 

Lamarck,  viii,   124,  342,  422,  405,  422- 

423. 
Lambdoiherium  popoafficum,  275. 
Lartet,  104,  254. 
Lankester,  96,  322,  333,  337, 
Laws -of  evolution,  the,  225. 
Least  resistance,  30. 
Leconte,  115. 
Leibnitz,  415. 

Leidy,  50,  85,  258,  364,  371,  376. 
Lepidoptera,  316. 
Leporidse,  375. 

Leptocardii,  317,  318,  319,  320. 
Lereboullet,  8,  60,  74,  75,  77,  124, 
Lespes,  57. 
Lewes,  G.  H.,  415. 
Line  of  the  Batrachia,  the,  331. 
Line  of  the  Pisces,  the,  324. 
Location  of  growth-force,  on  the,   24, 

195,  205. 
Locke,  438. 


Loew,  0.,  430. 
Lombard,  418. 
Lophiodon,  247. 
Lophodont  type,  243. 
Loss  of  growth-force,  201. 
Loup  Fork  fauna,  302. 
Loxolophodonts,  248,  250,  259. 
Luchatze  negro  woman,  287. 
Lund,  367. 
Lvcodon,  4. 

Mammalia^  278. 

Mammalia  educabilia,  ix,  241. 

Mammalian  line,  the,  341. 

Man,  development  of,  123, 146,  155,  267, 
278. 

3f uncus  macrolipis,  84. 

Mandibular  teeth,  the,  245,  249. 

Manner  of  evolution,  the,  6,  11. 

Marsh,  0.  C,  x,  258,  277,  308,  333,  340. 

Marsipobranchii,  316,  317,  318,  319, 
320. 

Marsupialia,  341-344,  317-348,  359. 

Mastodon  ohioticus,  56. 

Maternal  impressions,  viii,  213. 

Maxillary  teeth,  the,  244,  246, 

McCook,  Dr.,  385. 

Meehan,  T.,  160,  161. 

Mechanical  evolution,  350. 

Meleagris,  24. 

"  Memoirs  Boston  Society  Natural  His- 
tory," 51. 

3fcnodus,  272. 

"  Mental  Physiology,"  438. 

Mcsodon  albolabris,  178. 

Mesonyx,  246,  278. 

Metachrosis,  211. 

Metaesthetism,  421. 

Metaphysical  evolution,  ix,  148,  378. 

Metaphysical  species,  on.  111. 

Metaphysics  of  evolution,  229. 

Method  of  creation  of  organic  types,  vii, 
11,  173,  229,  241,  353. 

Mimetic  analogy,  viii,  104,  212. 

Mind,  development  of,  214,  385,  445. 

Minot,  C.  S.,  287. 

Mioclacnus  corruffatiis,  275, 

Mivart,  15,  28. 


4:64: 


INDEX. 


Modifications  of  animals  under  domesti- 
cation, 110. 
Monas,  27. 
Mongolian,  288. 
Monism,  421. 

Monodelphia,  344,  347,  348. 
Monotremata,  341,  346,  347. 
Morals  of  evolution,  the,  236,  311. 
Morris,  C,  385. 
Miiller,  8,  325. 
Murphy,  194. 
MustelidaB,  246. 
Mutilla,  212. 
Mycelium,  30. 
Myiodioctes  canadensis^  85. 

Naja,  4. 

Natural  selection,  2,  14,  43,  78,  106,  107, 

174,  175. 
Nature  of  actions,  the,  439. 
Nautilus,  18. 
Necturus,  333. 
Necturus  maculatuii^  49. 
Negro,  288. 
Neurism,  20,  205. 
Numida,  24. 
Neuroptera,  316. 
Newton,  14. 
Nimravus  gomphodus^  375, 

(Estridae,  316. 

Office  of  consciousness,  412. 

Oken,  7. 

Omnivora,  371. 

Oncocephalus  griscus,  90. 

Ophiholus,  299. 
triangulus^  197. 

Opbidia,  334,  335. 

Oporornis  agilis,  85. 
formosus,  85. 

Orconeetes  pcUucidus,  1 3 . 

Origin  of  automatic  movements,  the,  393. 

Origin  of  consciousness,  402. 

"  Origin  of  the  Fittest,"  xiii,  175,  225. 

Origin  of  the  foot-structure  of  the  un- 
gulates, xi,  368. 

"Origin  of  Genera,"  vi,  vii,  11,  41,  125, 
256. 


Origin  of  inexact  parallelism,  92. 

Origin  of  intelligence,  31. 

Origin  of  the  modern  types  of  bunodont 

and  lophodont  dentition,  251. 
Origin  of  motives,  450. 
Origin  of  the  specialized   teeth  of  the 

carnivora,  xi,  363. 
Origin  of  species,  2,  7,  42,  107. 
Origin  of  the  will,  x,  437. 
Ornithorhynchus,  184. 
Ornithosauria,  335,  336. 
Orthagoriscidse,  330. 
Orthoceras,  18. 
Osborn,  H.,  277. 
Ossemens  fossiles,  49,  176, 
Osteocephalus,  46,  221. 
Ostraciontidas,  330. 
Owen,  Sir  K.,  88,  91,  lOS,  318. 
Oxyaena,  246,  360. 
Oxycena  lupina^  365. 

morsitans,  375. 
Oxyrrhopus,  4. 

Packard,  A.  S.,  2,  13. 

Palaeosyops,  247. 

Palaeotheriodont,  258. 

Palaeotherium,  247,  248. 

Paleontological  bulletins,  xii. 

Paleontological  evidence,  383. 

Palingenesis,  126. 

Pangesthetism,  419. 

Pantolambda,  360. 

Pantolambda  hathmodon^  275. 

Parallelism,  7. 

Parallelism  in  higher  groups,  58. 

Parker,  86. 

Pasteur,  431. 

Pavo,  24. 

Pelycodus,  360. 

Perca,  4. 

Percomorphi,  328,  331. 

Perigenesis,  ix. 

Periptychus,  359. 

Periptychus  rhahdodon,  268,  308. 

Pcrissodactyla,  250,   265,  3^'8,  371-373, 

375,  399. 
Permian  fauna,  302. 
Peters,  336. 


INDEX. 


465 


Pharyngognathi,  330,  331. 

Phenacodus,  301. 

Phenacodus primoevus,  270,  273,  275,  300, 

808. 
vortmani,  345. 
"Philosophie  Zoologique,"  viii,  423. 
Phrenism,  205. 
Physical  evolution,  128. 
Physical  origin  of  man,  the,  146. 
Physiophilosophs,  7. 
Physoclysti,  328. 
Physostomi,  328. 
Pityophis  sayi,  197. 
Plagiaulax,  348. 
Platypodidse,  346. 
Plecostomus,  4. 
Plectognathi,  330. 
Plesiosaurus,  26,  188. 
Pleuronectidse,  196. 
Pliauchenia,  223. 
Poebrotherium,  223. 
Poebrotherium  labiatum,  271,  370. 

vilsoni,  371,  376. 
Polycystina,  27. 
Polyphyletic  descent,  vii. 
Porter,  Noah,  xi. 
Pressure,  effect  of,  228. 
"Primitive  Types  of  Mammalia  Educa- 

bilia,"  246. 
*'  Principles  of  Biology,"  ix,  xi,  423. 
"  Principles  of  Psychology,"  ix. 
Procelurus  julieni,  366. 
Probable  cases  of  transition,  83. 
Proboscidia,  233,  265,  342-4,  346-8,  375, 

401. 
Procamehis  occidentalis,  308,  376. 
Procyonidee,  359. 
Prostemma  gutiula^  89. 
Protamoeba,  190. 
Proteida,  331-3. 
Proteles,  349. 
Protobathybius,  420. 
Protohippus  sejundtis,  271,  370. 
Protolabis,  223. 
Protozoa,  33,  420. 
Ptychodont  type,  243. 
Ptychostomus,  4. 
Ptychosiomus  pidiensis,  213. 
80 


Puerco  fauna,  302. 
Pygopodidae,  337. 
Pythonomorpha,  26,  334. 

Quadrumana,  179,  278,  280,  342-4,  347, 
385,  899,  400,  401. 

Radcliffe,  20. 
Ptadiata,  27. 
Rana,  4. 
Rana  affilis,  222. 

affijiis,  47,  84. 

areolata^  48. 

catcsheiana,  48. 

clamata,  222. 

corrugata,  48. 

cyanopldydisy  48. 

delalandii,  47. 

ehrenhergii,  48. 

fasdata,  47. 

fuscigultty  48. 

gracilis^  48. 

grayi,  47. 

grunniens,  48. 

hexadactyla,  48,  222. 

mascariensis,  47. 

occipitalis,  48. 

oxyrhyncJms,  47,  222. 

palmipes,  47. 

porosissima,  47. 

temporaria,  84. 

tigrina,  48. 

vittigera,  48. 
Raniformia,  217. 
Ranula  chrysoprasina,  222. 
Rathke,  57,  61,  76,  93. 
Rationale  of  moral  development,  166. 
Rattle  of  the  rattlesnake,  the,  197. 
Raymond,  Dubois,  21,  409,  415. 
Relation  of  animal  motion  to  animal  evo- 
lution, xi,  266,  350. 
Rationale  of  the  development  of  intelli- 
gence, 154. 
Relation  of  man  to  the  tertiary  mamma- 
lia, X,  268. 
Relations  of   nearly  allied  genera,   on 

the,  44. 
Relations  of  physical  and  moral  nature, 
158. 


466 


INDEX. 


Eelations  of  the  types  of  dentition  to 

types  of  foot,  260. 
Repetitive  addition,  180. 
"Report  on  Geological  Survey  of  Mon- 
tana, Wyoming,  etc.,"  246. 
"  Report  United  States  Exploring  Survey 

W.  lOOth  Meridian,"  224. 
Reptilian  line,  the,  333, 
Respiratory  and   circulatory    system   of 

vertebrates.  196. 
Retardation,  vi,  13,  142,  182,  281,  385. 
Retardation  and  acceleration,  11,  43,  15, 

115,  226. 
Retrograde   metamorphosis    of   energy, 

427. 
"  Review  of  Birds  of  North  America,"  55. 
Review  of  modern  doctrine  of  evolution, 

xi,  215. 
Rhachitomi,  331,  332. 
Rhinocerus,  247. 
Rhynchocephalia,  334,  336. 
Riickhard,  Rabl,  319. 
Roccus  lineatus,  213. 
Rodentia,  180,  342-4,  346,  375, 
Rotifera,  315. 
Ruminantia,  223,  247,  375. 
Ryder,  J.  A.,  ix,  368,  409,  423. 

Sacculina,  401. 
Salamandra  atra,  87. 

maculosa,  87. 
Salmo,  4. 
Salticus,  212. 
Saturniidae,  316. 
Sauropterygia,  334,  336. 
ScaridsD,  331.      . 
Schlosser,  370. 
Schopenhauer,  453. 
Schopfungsgeschichte,  xiii. 
Schreiber,  87. 
Scincidae,  337. 
Sclater  and  Salvin,  118. 
Scolecophidia,  340. 
Scombridge,  331. 
Scops  asio,  4. 
Seeley,  H.  G.,  335,  340. 
Segment-repetition,  182. 
fSelenodonts,  247. 


Serranidae,  331. 

Siluridae,  327. 

Simia  satyrus,  283. 

Simiidae,  180. 

Siredon,  333. 

Sirenia,  342,  347,  349. 

Smilodoti  neogceus,  367. 

Smith,  Aubrey,  86. 

Smyth,  Brough,  291. 

Spelerpes,  4. 

Spencer,  Herbert,  viii,  ix,  xi,  2,  15,  413, 

444,  445,  448. 
Spinoza,  90,  456. 

Spiritual  or  moral  development,  157. 
Spizclla  pusilla,  16. 

socialis,  16. 
Stegocephali,  331,  332. 
Stegophilus,  327. 
Steindachner,  86. 
St.-Hilaire,  91,  146. 
Streptostylica,  334. 
Structural   evidence   of    evolution,   the, 

241. 
Stypolophus,  246. 

whitice,  360. 
Subordinate    types   of    bunodonts,   the, 

244. 
Subordinate  types  of    lophodonts,   the, 

246. 
Successional  relation,  7. 
Survival  of  the  fittest,  15. 
Swainson,  96. 

Symborodonts,  248,  250,  257. 
Synopsis  of  the  vertebrata  of  the  eocene 

of  New  Mexico,  245. 
Synthesis  of  repetition,  187. 

Taenia,  184. 
Taeniodonta,  343,  349. 
Tachyglossidae,  346. 
Talpa,  360. 
Tapirodonts,  247,  255. 
Tapirus,  247. 
Taxeopoda,  342,  347. 
Taxodium  distichum,  86. 
TeidaD,  337. 
Teleology,  7,  16. 
Teleostomi,  318,  324-326, 


INDEX. 


467 


"Tertiary    Planorbis     of    Steiuhcira," 

408. 
Testudinata,  334. 
Testudinidae,  33Y. 
Theory  of  evolution,  x,  124. 
Theromorpha,  333,  335,  3oY. 
Thomson,  Sir  William,  431,  442. 
Thulie,  288. 
Tillodonta,  343. 
Tillotherium,  248. 
Topinard,  290. 
Tortricidae,  340. 
Trachystomata,  331,  332,  333. 
Trematoda,  401. 
Trichechodonts,  248,  255. 
Trichodiscus,  27. 
Triodopsis  tridentata^  178. 
Tritubercular  type  of  molar  teeth  in  the 

mammalia,  xii,  359. 
Tropidonotits  sipedon^  197. 
Tryon,  G.  W.,  177. 

Types  of  mammalian  molars,  the,  241. 
Typhlichthys  subfei'raneiis,  1 3. 
Typhlogeophis,  340. 

Uhler,  P.  Ft.,  90. 
Uintatherium,  248,  274,  278. 
Uintai/ierium  cornuium,  277. 

mirabile,  277,  308. 
Unconscious,  the,  391. 
Unconscious  cerebration,  32. 
Ungulata,  347,  359,  365,  369,  374. 
Unity  in  variety,  7. 
Urochorda,  322,  323. 


Urodela,  331,  332. 

Use  and  effort,  ix,  6,  194. 

Vegetable  growth,  force  of,  31. 

Velia,  90. 

Venus  of  the  Capitol,  292. 

Vermes,  399. 

Vertcbrata,  352,  356. 

Vertebrate  line,  the,  318. 

Vibrio,  188,  192. 

Viverridae,  245. 

Vogt,  C,  12,  401,  402. 

Von  Baer,  vi,  8,  46,  60,  62,  74,  77,  92. 

Von  Siebold,  86. 

Wagler,  88,  95. 

Walker  prize,  viii. 

Wallace,  13,  14,  15,  106,  174,  405. 

Wallace  and  Bates,  212. 

Ward,  Lester,  430. 

Wasatch  fauna,  302. 

Wheeler,  G.  M.,  v,  224,  317,  359,  365- 

369,  375,  376. 
Westwood,  89. 
Whiteavcs,  323. 
White  river  fauna,  301,  302. 
Wiegmann,  95,  100. 
Will,  208,  210,  434,  456. 
Willis,  Dr.,  438. 
Wrestler,  the,  289. 
Wortman,  J.  L.,  104,  275. 
Wyman,  87. 

"* 
"  Zoologie  Philosophique,"  342,  423. 


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and  periods  in  its  manifestation.  The  influences  of  age,  sex,  constitution,  climate,  Hefis»m, 
occupation,  religion,  prevailing  ideas,  the  elements  of  character,  the  tendencies  of  civiliza- 
tion, are  comprehensivelv  analyzed  in  their  bearing  upon  the  propensity  to  pelf-dcBtruc- 
t  on.  Professor  Morseili  is  an  eminent  European  authority  on  this  subject.  It  is  accom- 
panied by  colorei  maps  illustrating  pictorially  the  results  of  statistical  inquiries. 

VOLCANOES : 

WHAT  THEY  ARE  AND  WHAT  THEY  TEACH.  By  J.  W.  Judd,  Profc?sor 
of  Geology  in  the  Royal  School  of  Mines  (London).  With  Ninetv-six  Illus- 
trations. "^12mo,  cloth.     12.00. 

"In  no  field  has  modern  research  been  more  fmitfal  than  in  that  of  which  ProrcB<^or 
tfudd  gives  a  popular  account  in  the  present  volume.  The  great  lines  of  dynamical,  geo- 
logical, and  meteorological  inquiry  converge  upon  the  grand  problem  of  the  interior  con- 
stitution of  the  earth,  and  the  vast  influence  of  subterranean  agencies.  .  .  .  His  book  is 
very  far  from  being  a  mere  dry  description  of  volcanoes  and  their  eruptions  ;  it  is  rather 
a  presentation  of  the  terrestrial  facta  and  laws  with  which  volcanic  phenomena  are  asso- 
ciated."—Pop?<tor  Science  Monthly. 

"The  volume  before  us  is  one  of  the  pleasantest  science  manuals  we  have  read  fcr 
Bome  iimQ.''''  —AthencEum. 

"Mr.  Judd's  summary  is  so  full  and  so  concise,  that  it  is  almost  impossible  to  give  a 
fair  idea  in  a  short  review." — FaU  Mall  Gazette. 

THE   SUN. 

By  C.  A.  Young,  Ph.  D.,  LL.  D.,  Professor  of  Astronomy  in  the  College  of  New 
Jersey.     With  numerous  Illustrations.     12mo,  cloth.     $2.00. 

"  Professor  Young  is  an  authority  on  '  The  Sun,'  and  writes  from  intimate  knowledge. 
He  has  studied  that  great  luminary  all  his  life,  invented  and  improved  instruments  for  ob- 
serving it,  gone  to  all  quarters  of  the  world  in  search  of  the  bes^t  places  and  opportunities 
to  watch  it,  and  has  contributed  important  discoveries  that  have  extended  our  knowledge 
ofit. 

"  It  would  take  a  cyclopaedia  to  represent  all  that  has  been  done  toward  clearing  up  the 
solar  mysteries.  Professor  Young  has  summarized  the  iutorniation,  and  presented  it  in 
a  form  completely  available  for  general  readers.  There  is  no  rhetoric  in  his  book:  he 
trusts  the  grandeur  of  his  theme  to  kindle  interest  and  impress  the  feelings.  His  stnte- 
ments  are  plain,  direct,  clear,  and  condensed,  thouch  ample  enough  for  his  purpose,  and 
the  substance  of  what  is  generally  wanted  will  be  found  accurately  given  in  jjis  pages." — 
Popular  Science  Monthly. 

ILLUSIONS : 

A  PSYCHOLOGICAL  STUDY.  By  James  Sully,  author  of  "  Sensation  and 
Intuition,"  etc.    12mo,  cloth.     $1.50. 

"  An  interesting  contribution  by  Mr.  James  Sully  to  the  study  of  mental  pathology. 
The  authors  field  of  inquiry  covers  all  the  phenomena  of  illusion  observed  in  sense-per- 
ception, in  the  introspection  of  the  mind's  own  feelings,  in  the  reading  of  otherg'  feelings, 
in  memory,  and  in  belief.  The  author's  conclusions  are  often  illustrated  by  concrete  ex- 
ample or  anecdote,  and  his  general  treatment  of  the  subject,  while  essentially  scientific,  is 
eufflciently  clear  and  animated  to  attract  the  general  reader."— AVm;  Yoi'k  Sun. 


New  York :  D.  APPLETON  &  CO.,  1,  3,  &  5  Bond  Street. 


SCIENTIFIC  PUBLICATIONS, 


The  Brain  and  its  Functions. 

By  J.  LuYS,  Physician  to  the  Hospice  de  la  Salpetriere.     With  Illustra- 
tions.    12mo.     Cloth,  11.50. 

•^'No  living  physiologist  is  better  entitled  to  speak -with  anthority  upon  the  structure 
and  fauctious  of  the  hrain  than  Dr.  Luys.  His  studies  on  the  anatomy  of  the  nervous 
system  are  acknowledged  to  be  the  fullest  and  mo&t  systematic  ever  undertaken.  Dr, 
Lays  supports  his  conclusions  not  only  by  his  own  anatomical  researches,  but  also  by 
many  functional  observations  of  various  other  physiolog-ists,  including  of  course  Professor 
Feurier's  now  classical  experiments." — St.  Jameses  Gazette. 

"■Dr.  Luys,  at  the  head  of  the  great  French  Insane  Asylum,  is  one  of  the  most  eminenit 
and  successful  investigators  of  cerebral  science  now  living;  and  he  has  given  unquestion- 
ably the  clearest  and  most  interesting  brief  account  yet  made  of  the  structure  and  opera- 
tions of  the  brain.  We  have  been  fascinated  by  this  volume  more  than  by  any  other  treatise 
we  have  yet  seen  on  the  machinery  of  sensibility  and  thought ;  and  we  have  been  instructed 
not  only  by  raucii  that  is  new,  but  by  many  sagacious  practical  hints  such  as  it  is  well  lor 
everybody  to  underscand.'" — The  Poplar  Science  Monthly. 

The  Concepts  and  Theories  of  Modem  Physica 

By  J.  B.  Stallo.     12mo.     Cloth,  ll.TS. 

"^  Judge  Stallo's  work  is  an  inquiry  into  the  validity  of  those  mechanical  conceptions 
of  the  universe  which  are  now  held  as  fundamental  in  physical  science.  He  takes  up  the 
l.^ading  modern  doctrines  which  are  based  upon  this  rueebanical  conception,  such  as  the 
atomic  constitution  of  matter,  the  kinetic  theory  of  gases,  the  conservation  of  energy,  the 
nebilar  hypothesis,  and  other  views,  to  find  how  much  stands  upon  solid  empirical  trround, 
and  how  much  rests  upon  metaphysical  speculation.  Since  the  appearance  of  Dr.  Draper's 
*•  Religion  and  Science,"  no  book  has  been  published  in  the  country  calculated  to  make  so 
deep  an  impression  on  thoughtful  and  educated  readers  as  this  volume.  .  .  .  The  range 
and  minuteness  of  the  author's  learning,  the  a<nteness  of  his  reasoning,  and  the  sineulai 
precision  and  clearness  of  his  style,  ara  qualities  which  very  seldom  have  been  jointly 
exhibited  in  a  scientifi.c  treatise.  "■ — Xem  York  Sun. 

The  Formation  of  Vegetable  Mould, 

THROUGH   Tim  ACTIOX   OF  WORMS,  WITH   OBSERTATIONS   ON 
THEIR  HABITS.      By  Charles  Daewix,  LL.  D.,  F.  R.  S.,  author  of  "  On 

the  Origin  of  Spedss^"  etc.,  etc      With  Illustratiori&.     12mOy  elotk     Price, 

$1.5a. 

"Mr.  Darwin''s  Tittle  volume  on  the-  habits  jmd  fnstfncts  erf  earth-worms  is  no  less 
marked  than  the  earlier  or  more  elaborate  etForts  of  his  genius  by  freshness  of  observation,, 
unfailing  power  of  interpreting  and  correlating  fact*,  and  logical  vigoF  in  generalizing 
upon  the?m.  The  main  purpose  erf"  the  work  is  to  point  out  the  share  which  worms  have 
taken  in  the  formation  of  the  layerof  vegetable  mould  which  covers  the  whole  surface  of 
the  land  in  every- modei-ately  humid  country.  All  lovers  of  nature  will  unite  in  thanking 
Mr.  Darwin  for  the  new  and  interesting  Ireht  he  has  thrown  upon  a  subject  so  long  over- 
looked, yet  so  fun  of  interest  and  instruction,  as  the  stnrcttrre  and  the  labors  of  the  earth- 
worm."— Satmiim/  Eeviem. 

"  Respecting  worms  as  among  the  most  useful  portions  of  anima'te  nature,  Dr.  Darwim 
relates,  fn  this  remarkable  book,  their  structure  and  hrsbits,  the  part  they  have  played  in 
the  burial  of  ancient  buDdirrgs  ani  the  denuda'tion  of  the  land,  in  the  di^intesration  of 
rocks,  the  preparation  of  soil  for  the  growth  ol  plants,  and  in  the  natural  history  of  the 
viQria.''— Boston  Advertiser. 


New  York:.  D.  APPLETOX  &:  CO.,,  1,  3,  &  5  Band  Street. 


SCIENTIFIC  PUBLICATIONS. 


Ants,  Bees,  and  Wasps. 

A  Record  of  Observations  on  the  Habits  of  the  Social  Ilymcnoptera.  By 
Sir  Joii-S  Lubbock,  Bart.,  M.  P.,  F.  R.  S.,  etc.,  author  of  "  Origin  of  Civiliza- 
tion, and  the  Primitive  Condition  of  Slan,"  etc.,  etc.  With  Colored  Plates. 
12mo,  cloth,  $2.00. 

"This  volame  contains  the  record  of  various  experiments  made  with  ants,  bees,  and  wasps  dur- 
in^r  the  last  ten  years,  with  a  view  to  test  their  mental  condition  and  j)Owei-s  of  sense.  The  prin- 
cipal point  in  which  ?ir  John's  mode  of  experiment  dift'ers  from  thost.-  of  lluber.  P^ord.  McCook, 
and  others,  is  that  he  has  carefully  watched  and  marked  particular  insects,  and  has  had  their 
nests  under  observation  for  Ions'  periods — one  of  his  ants'  nests  havinj,'  been  imder  c<mstatit  in- 
spection ever  since  1S74.  His  observations  are  made  principally  uj)on  ants  because  they  show 
more  power  and  flexibihty  of  mind;  and  the  value  of  his  studies  is  that  they  belong  to  the  de- 
partment of  original  research." 

"  We  have  no  hesitation  in  saying  that  the  author  has  presented  \is  with  the  most  valuahie 
series  of  observations  on  a  special  subject  that  has  ever  been  produced,  charuiingly  written,  full  of 
logical  deductions,  and,  when  we  consider  his  multitudinous  engagements,  a  remarkable  illus- 
tration of  economy  of  time.  As  a  contribution  to  insect  psychology,  it  will  be  long  before  this 
boot  finds  a  parallel." — London  Athenceum. 

Diseases  of  Memory : 

An  Essay  in  the  Positive  Psychology.    By  Tii.  Ribot,  author  of  "  Heredity," 

etc.     Translated  from  the  French  by  William  IIlntingtox  Smith.     12mo, 

cloth,  $1.50. 

"M.  Eibot  reduces  diseases  of  memory  to  law,  and  his  treatise  is  of  extraordinary  interest.*' 
—Philadelphia  Press. 

"Not  merely  to  scientific,  but  to  all  thinking  men,  this  volume  will  prove  intensely  interc:£t- 
ing."— A'ezy  York  Observer. 

"M.  Ribot  has  bestowed  the  most  painstaking  attention  upon  bis  theme,  and  numerous  ex- 
amples of  the  conditions  considered  greatly  increase  the  value  and  interest  of  the  volume." — 
Philadelpkia  North  American. 

'•To  th«  general  reader  the  work  is  made  entertaining  by  many  illustratiors  connected  with 
6uch  namt'j  as  Linnaeus,  Newton,  Sir  Walter  Scott,  Horace  Vernet,  Gustave  Dore,  and  many 
others."—  larrishurg  Telegraph. 

"Th^  whole  subject  is  presented  with  a  Frenchman''s  vivacity  of  style." — Providence  Jonrnah 

"  It  is  not  too  much  to  say  that  in  no  single  work  have  so  many  curious  cases  been  brouglit 
together  and  interpreted  in  a  scientific  manner." — Boston  Evening  Tr at elkr. 

Myth  and  Science. 

By  Tito  Yignoli.     12mo,  cloth,  price,  $1.50. 

"  His  book  is  ingenious  ;  .  .  .  his  theory  of  how  science  gradually  differentiated  from  and  con- 
quered myth  is  extremely  well  wrought  out,  and  is  probably  in  essentials  correct." — Saturduy 
xieview. 

"The  book  is  a  strong  one,  and  far  more  interesting  to  the  general  reader  than  its  title  would 
indicate.  The  learning,  the  acuteness,  the  strong  reasoning  power,  and  the  scientific  spirit  of  the 
author,  command  admiration."— iVeiw  Yu?'k  Chiistian  Advocate. 

"  An  attempt  made.  Avith  much  ability  and  no  small  measure  of  success,  to  trace  the  origin  and 
development  of  the  myth.  The  author  has  pursued  his  inquiry  with  much  patience  and  ingenuity, 
and  has  produced  a  very  readable  and  luminous  treatise.''' —p'hiladelphia  JVorth  Ainerican. 

"  It  13  a  curious  if  not  startling  contribution  both  to  psychology  and  to  the  em-ly  history  ol 
man's  development." — New  York  World. 


Sold  by  all  booksellers ;    or  sent   by  mall,  post-paid,  on  receipt  of  price. 


N'ew  York :  D.  APPLETOX  &  CO.,  1,  3,  «fe  5  Bond  Street. 


SCIENTIFIC    PUBLICATIONS. 

Man  before  Metals. 

By  N.  Jolt,  Professor  at  the  Science  Faculty  of  Toulouse  ;  Correspondent 
of  the  Institute.     With  148  Illustrations.     12mo.     Cloth,  $1.75. 

"  The  discussion  of  man's  origin  and  early  history,  by  Professor  De  Quatrefages,  formed  one 
of  the  most  useful  volumes  in  the  '  International  Scfentific  Series,'  and  the  same  collection 
is  now  further  enriched  by  a  popular  treatise  on  paleontology,  by  M.  N.  Joly,  Professor  in  the 
University  of  Toulouse.  The  title  of  the  book,  '  Man  before  Metals,'  indicates  the  limitations  of 
the  writer's  theme.  His  object  is  to  bring  together  the  numerous  proofs,  collected  by  modern 
research,  of  the  sreat  age  of  the  human  race,  and  to  show  us  what  man  was.  in  respect  of  cus- 
toms, Industries,  and  moral  or  religious  ideas,  before  the  use  of  metals  was  known  to  him.'' — 
New  York  Sun. 

"■  An  interesting,  not  to  say  fascinating  volume." — New  YorJc  Churchman. 

"  M.  Joly's  book  sums  up  the  discoveries  of  modern  science  bearing  on  the  primeval  history 
of  man,  on  the  antiquity  of  the  human  race,  and  on  the  circumstances  attending  its  slow  and 
partial  ascent  to  the  modern  level  of  civilization.  It  also  presents  with  brevity  but  thoroughness 
the  generally  accepted  theories  relating  to  the  habits  and  environment  of  primitive  man.  Its 
usefulness  and  interest  are  much  increased  by  numerous  and  excellent  illustrations." — Pkiladel- 
phia  North  Amencan. 

"  This  is  a  book  worth  owning." — New  Toric  Christian  Advocate. 

Animal  Intalligence. 

By  George  J.  Romanes,  F.  R.  S.,  Zoological  Secretary  of  the  Liunsean 
Society,  etc.     12mo.     Cloth,  %l.1o. 

"  My  object  in  the  work  a3  a  whole  is  twofold  :  First,  I  have  thought  it  desirable  that  there 
should  be  something  resembling  a  text-book  of  the  focts  of  Comparative  Psychology,  to  which 
men  of  science,  and  also  metaphysicians,  may  turn  whenever  they  have  occasion  to  acquaint 
themselves  with  the  particular  level  of  intelligence  to  which  this  or  that  species  of  animal 
attains.  My  second  and  much  more  important  object  is  that  of  considering  the  facts  of  animal 
Intelligence  in  their  relation  to  the  theory  of  descent." — From  the  Preface. 

"  Unless  we  are  greatly  mistaken,  Mr.  Eomanes's  work  will  take  its  place  as  one  of  the  most 
attractive  volumes  of  the  '  International  Scientific  Series.'  Some  persons  may,  indeed,  be  dis- 
l)osed  to  say  that  it  is  too  attractive,  that  it  feeds  the  popular  taste  for  the  curious  and  marvelous 
without  supplying  any  commensurate  discipline  in  exact  scientific  reflection :  but  the  author  has, 
we  think,  fully  justified  himself  in  his  modest  preface.  The  resnlt  is  the  appearance  of  a  collec- 
tion of  facts  which  will  be  a  real  boon  to  the  student  of  Comparative  Psychology,  for  this  is  the 
first  attempt  to  present  systematically  well-assured  observations  on  the'mental  life  of  animals. 
—Saturday  Revieiv. 

"The  author  believes  himself,  not  without  ample  cause,  to  have  completely  bridged  the  sup- 
posed gap  between  instinct  and  reason  by  the  authentic  proofs  here  marshaled  of  remarkable 
Intelligence  in  some  of  the  higher  animals.  It  is  the  seemingly  conclusive  evidence  of  reasoning 
powers  furnished  by  the  adaptation  of  means  to  ends  in  cases  which  can  not  be  explained  on  the 
theory  of  inherited  aptitude  or  habit."' — 2\ew  York  Sun. 

The  Science  of  Politics. 

By  Sheldon  Amos,  M.  A.,  author  of  "  The  Science  of  Law,"  etc.     12mo. 
Cloth,  ll.YS. 

"  It  is  an  able  and  exhaustive  treatise,  within  a  reasonable  compass.  Some  of  its  conclusions 
will  be  disputed,  although  sterling  common  sense  is  a  characteristic  of  the  book.  To  the 
political  student  and  the  practical  statesman  it  ought  to  be  of  great  value."— Aew  York  Herald. 

"The  author  traces  the  subject  from  Plato  and  Aristotle  in  Greece,  and  Cicero  m  Eome,  to 
the  modern  schools  in  the  English  field,  not  slighting  the  teachings  of  the  American  Eevolution 
or  the  lessons  of  the  French  Revolution  of  1793.  Forms  of  g-overnment,  pohtical  terms,  the 
relation  of  law,  written  and  unwritten,  to  the  subject,  a  codification  from  Justinian  to  Napoleon 
in  France  and  Field  in  America,  are  treated  as  parts  of  the  subject  in  hand.  Necessarily  the 
subjects  of  executive  and  legislative  authority,  police,  liquor,  and  land  laws  are  considered,  and 
the  question  ever  growing  in  importance  in  all  countries,  the  relations  of  corporations  to  the 
state." — Neio  York  Observer. 


New  York :  D.  APPLETON  &  CO.,  1,  3,  &  5  Bond  StreeL 


D.  APPLETON  &   CO.'S   PUBLICATIONS. 

CHAPTERS    IN    POI.ITICAL    ECONOMY.      By  Albert  S.  Bolles, 

Lecturer  on  rolitical  Economy   in   the    Boston  University.     Square  12ttio. 

Cloth,  11.50. 

CONTENTS.— The  Field  and  Importance  of  Political  Economy  :  The  Payment  of 
Labor;  On  the  Increase  of  Wages;  Etiect  of  Machinery  on  Labor  ;  On  the  Meaning  and 
Causes  of  Value  ;  A  Measure  of  Value ;  Money  and  its  Uses  :  Decline  in  the  Value  of  Gold 
and  Silver;  The  Money  of  the  Future;  The  Good  and  Evil  of  Banking;  The  Financial 
Panic  of  1873;  Relation  of  Banks  to  Speculators;  Influence  of  Credit  on  Prices  ;  On  Legal 
Interference  with  the  Loan  of  Money,  Payment  of  Labor,  and  Contracts  of  Corporations  ; 
Advantages  of  Exchange ;  Taxation. 

FINANCIAL    HISTORY    OF    THE     UNITED    STATES    FR03I 

1774   TO    1789,  EMBRACING   THE   rEKIOD    OF   THE   AMERICAN 

REVOLUTION.     By  Albert  S.  Bolles.     8vo.     Cloth,  S2.50. 

"  It  fills  a  place  and  meets  a  want  which,  so  far  as  my  observation  extends,  is  not  pup- 
plied  by  any  one  publication." — David  A.  Wells. 

FINANCIAL    HISTORY    OF    THE    UNITED     STATES     FROM 

1789   TO    18G0.     By  Albert  S.  Bolles.     8vo.     Cloth,  $3.50. 

FINANCIAL     HISTORY    OF    THE     UNITED    STATES     FR03I 

1861  TO  1885.     By  Albert  S.  Bolles.     8vo.     Cloth,  $3.50. 

NOMISMA  ;  OR,  "  LEGAL  TENDER."  By  Henri  Cernuschi,  author  of  "  Bi- 
Metallic  Money."     12mo.     Cloth,  $L25. 

The  principal  part  of  the  information  contained  in  this  volume  was  given  by  the  author, 
before  a  commission  appointed  by  Congress,  for  the  purpose  of  ascertaining  whether  it 
was  feasible  for  the  United  States  to  introduce  a  bi-metallic  standard  of  gold  and  silver. 

The  author  is  an  authority  on  tinance  in  France. 

ON  THE  PROBABLE  FALL  IN  THE  VALUE  OF  GOLD.   By 

Michel  Chevalier.     Translated  by  Richard  Cobden.     Svo,     Cloth,  §1.25. 

WEIGHTS,    MEASURES,    AND    MONEY    OF    ALL    NATIONS. 

Compiled  by  F.  W.  Clarke,  S.  B.,  Professor  of  Physics  and  Chemistry  in  the 
University  of  Cincinnati.     12mo.     Half  bound,  $1.50. 

HAND-BOOK    OF    SOCIAL    ECONOMY;    OR,  THE   WORKER'S   A 

B  C.     By  Edmond  About.     12mo.     Cloth,  $2.00. 

CONTENTS.— M.VL-a:%  Wants;  Useful  Things;  Production;  Parasites;  Exchange; 
Liberty;  Money;  Wases;  Savings  and  Capital;  [Strikes;  Co-operation;  Assurance,  and 
some  other  Desirable  Novelties. 

POLITICAL  ECONOMY.  By  W.  Stanley  Jetons,  Professor  of  Logic  and 
Political  Economy  in  Owens  College,  Manchester.  ISmo.  Flexible  cloth, 
45  cents. 

MONEY  AND  THE  MECHANISM  OF  EXCHANGE.  By  W.  Stan- 
ley Jeyons.     12mo.     Cloth,  $1.'75. 


New  York :   D.  APPLETON  &  CO.,  Publishers,  1,  3,  &  5  Bond  Street. 


D.  APPLETON  &  CO.'S   PUBLICATIONS. 


PRINCIPLES  OF  POLITICAL  ECONOMY,  WITH  SOME  OF 
THEIR   APPLICATIONS   TO   SOCIAL   PHILOSOPHY.      By 

John  Stuart  Mill.     2  vols.     8vo.     Cloth,  $4.00 ;  half  calf,  extra,  $8.00. 

In  the  whole  range  of  extant  authorship  on  political  economy,  there  is  no  writer  except 
Aflam  Smith  with  whom  John  Stuart  Mill  can,  without  injustice,  be  compared,  in 
originality,  Adam  Smith,  as  being  the  acknowledged  father  of  the  science,  takes  the  pre- 
cedence, as  he  does  also  in  exuberance  of  apt  illustration.  But  in  rectitude  of  understand- 
ing, clearness,  and  sagacity,  Mill  is  fully  his  peer;  in  precision  of  method,  range  of  topics, 
and  adaptation  to  the  present  state  of  society,  he  is  altogether  his  superior.  The  '•'Wealth 
of  Nations  "  now  belongs,  indeed,  rather  to  the  history  of  the  science  than  to  its  exposi- 
tion. But  the  "Principles  of  Political  Economy"  is'an  orderly,  symmetrical,  and  lucid, 
exposition  of  the  science  in  its  present  advanced  state.  In  extent  oi"  information,  breadth 
of  treatment,  pertinence  of  fresh  illustration,  and  accommodation  to  the  present  wants  of 
the  statesman,  the  merchant,  and  the  social  philosopher,  this  work  is  unrivaled.  It  is 
written  in  a  luminous  and  smooth,  yet  clear-cut  style;  and  there  is  diffused  over  it  a  soft 
atmosphere  of  feeling,  derived  from  the  author's  unaffected  humanity  and  enlightened  in- 
terest in  the  welfare  of  the  masses. 

MILL^S  PRINCIPLES  OF  POLITICAL  ECONOMY  :  ACniDGED, 
WITH  CRITICAL,  BIBLIOGRAPHICAL,  AND  EXPLAXATORY  XOTES, 
AXD  A  SKETCH  OF  THE  HISTORY  OF  POLITICAL  ECONOMY.  By 
J.  Laurence  Laughlix,  Ph.  D.,  Assistant  Professor  of  Political  Economy  in 
Harvard  University.  With  Twenty-four  Maps  and  Charts.  A  Text-Book  for 
Colleges.     8vo.     658  pages.     Cloth,  $3.50. 

"An  experience  of  five  years  with  Mr.  Mill's  treatise  in  the  class-room  convinced  me, 
not  only  of  the  great  usefulness  of  what  still  remains  one  of  the  most  lucid  and  systematic 
books  yet  published  which  cover  the  whole  range  of  the  study,  but  I  have  also  been  con- 
vinced of  the  need  of  such  additions  as  should  give  the  results  of  later  thinking,  without 
militating  against  the  general  tenor  of  Mr.  Mill's  system  ;  of  such  illustrations  as  should 
fit  it  better  for  American  students,  by  turning  their  attention  to  the  application  of  princi- 
ples in  the  facts  around  us ;  of  a  bibliography  which  should  make  it  easier  to  get  at  the 
writers  of  other  schools  who  offer  opposing  views  on  controrerted  questions  :  and  of  some 
attempts  to  lighten  those  parts  of  his  work  in  which  Mr.  Mill  frightened  away  the  reader 
by  an  appearance  of  too  great  abstractness,  aud  to  render  them,  if  possible,  rnore  easy  of 
comprehension  to  the  student  who  first  appioacbes  Political  Economy  through  this 
author.-'— i^^AOWi  Preface. 

THE  STUDY  OF  POLITICAL  EC0IV03IY.  HIXTS  TO  STU- 
DEXTS  AXD  TEACHERS.  By  J.  LaurExVce  Laughlin,  Ph.  D.,  Assistant 
Professor  of  Political  Economy  in  Harvard  University.    16mo.    Cloth,  $1.00. 

"The  existence  of  this  little  book  is  due  to  an  attempt  to  convey,  by  lectures  to  students^ 
an  understanding  of  the  position  which  political  economy  holds  in  regard,  not  merely  to 
its  actual  usefulness  for  every  citizen,  but  to  its  disciplinary  power.  .  .  .  The  interest 
which  the  public  now  manifests  in  economic  studies  led  me  to  put  the  material  of  my  lect- 
ures into  a  general  form,  in  order  that  they  might  assist  inquirers  in  any  part  of  the 
country."— i^rcwi  Preface. 

THE  HISTORY  OF  BIMETALLIS3I  IN  THE  UNITED  STATES. 

By  J.  Laurence  Laughlix,  Ph.  D.,  Assistant  Professor  of  Political  Economy 
in  Harvard  University.     12mo.     Cloth. 

MONEY.     By  Charles  Moran.     12mo.     Cloth,  $1.25. 


New  York :   D.  ^VPPLETOX  &  CO.,  Publishers,  1,  3,  &  5  Bond  Street. 


D.  APPLETON   &    CO.'S   PUBLICATIONS. 


THE  MAN  VERSUS  THE  STATE:  containing  " The  New  Toryism,*^ 
"The  Coming  Slavery,"  "The  Sins  of  Legislators,"  and  "The  Great  Puliti. 
cal  Superstition,"  liy  Herbert  Spencer.  With  a  Postscript.  Small  8vo. 
Paper,  30  cents. 

"  Though  written  by  an  Englishman,  with  primal  reference  to  abuses  in  his  own  land, 
overy  wordof  theui  is  just  as  applicable  to  mischievous  teuduucies  orresiiltsin  the  L'uited 
States.  No  American  lias  yet  attacked  our  besetting?  t?ins  oi'  over-lej;i8latioii  with  the  vigor 
of  Mr.  Spencer.  Men  of  all  parties  should  read  his  earnest  warniniis  a^jainst  the  periloue 
drift  of  that  spirit  of  interference  and  meddlinjr  with  private  concerns  of  which  every 
year  we  see  many  evidences  at  Washington  and  all  the  State  capitals."— iN'ei^;  York  Jour- 
nal of  Commerce. 


DYNAMIC  SOCIOLOGY,  or  Applied  Social  Science,  as  based  upon 
Statical  Sociology  and  the  Less  Complex  Sciences.  By  Lester  F. 
Ward,  A.  M.     Two  volumes,  12mo.     Cloth,  $5.00. 

"In  his  two  volumes,  containing  upward  of  1,300  pages,  Mr.  Ward  takes  us  from  the 
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'  Bio»eny,' and  '  Sociogeny,' to  the  consideration  of  some  of  the  most  complex  problems 
presented  to  the  student  of  lite,  mind,  morals,  and  society.  Especially  interesting  are 
Mr.  Ward's  reflections  upon  the  Reproductive  Forces,  which  he  very  sensibly  and  success- 
fully vindicates  from  the  oppi-obrium  with  which  superficial  prejudice  has  surrounded 
them,  and  we  would  particularly  recommend  to  all  those  who  take  interest  in  social  ques- 
tions, and  who  are  capable  of  free  and  unbiased  thought,  his  remarks  upon  3Iarriage  In- 
stitutions. 

"  We  are  glad  to  find  that  Mr.  Ward  strongly  dissents  from  the  views  expressed  with 
such  curious  emphaj^is  by  Mr.  Herbert  Spencer  upon  the  subject  of  compulsory  state  educa- 
tion. A  consideration  of  the  matter,  means,  and  method  of  education  brings  to  its  con- 
clusion a  work  from  which  all  readers,  whether  or  not  they  agree  with  the  doctrines  therein 
expounded,  can  not  fail  to  derive  benefit,  more  especially  if  they  are  capable  of  brintring  to 
its  consideration  a  mind  divested  of  prejudice,  and  only  desirous  of  the  truth." — The 
Westminster  Be  view. 


CONFLICT  IN  NATURE  AND  LIFE:  A  Study  op  Antagonism  in 
the  Constitution  op  Things.  For  the  Elucidation  of  the  Problem  of  Good 
and  Evil,  and  the  Keconciliation  of  Optimism  and  Pessimism.     12mo,  cloth, 

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sanitary,  and  moral  questions  that  are  now  more  and  more  everywhere  tlirusting  them- 
eelves  into  prominence.  If  the  reconciliation  of  the  two  great  forces  of  Good  and  Evil  is 
not  here  made  complete  to  the  understanding  of  every  reader,  the  author  can  at  least  feel 
that  he  has  come  as  near  the  mark  as  any  one— and  he  has  certainly  presented  a  mass  of 
very  interesting  facts  to  the  reader,  the  result  of  what  must  have  been  a  lifetime  of  active 
etiidy  and  thoughtful  observation." — Hartford  Times. 

"A  semi-religious  work  covering  one  of  the  most  interesting  fields  of  thought  and 
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REFORMS:     THEIR    DIFFICULTIES    AND    POSSIBILITIES. 

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which  discusses  current  projects  for  reform  in  an  impartial  aud  searching  manner,  and  iu 
a  style  to  enlist  the  interest  of  all  intellectual  readers. 


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THE  ELEMENTS  OF  ECONOMICS.     By  Hexrt  Dunning  Macleod,  M. 
A.,  of  Trinity  College,  Cambridge ;  Lecturer  on  Political  Economy  in  the  Uni- 
versity of  Cambridge.     Volumes  I  and  II.     12mo.     Cloth,  $1.'75  each. 
"  The  author  attempts  to  establish  an  exact  science  of  economics  on  a  mathe- 
matical basis — to  establish  '  a  new  inductive  science  ' ;  and  he  presents  what  he 
calls  '  a  new  body  of  phenomena  brought  under  the  dominion  of  mathematics.'  " — 
New  York  World. 

PROGRESS  AND  POVERTY.  An  Inquiry  into  the  Cause  of  Industrial 
Depressions,  and  of  Increase  of  Want  with  Increase  of  Wealth  :  The  Remedy. 
By  Henry  George.     Cheap  edition.     12mo.     Cloth,  .$1.00. 

"  '  Progress  and  Poverty '  is  not  merely  the  most  original,  the  most  striking 
and  important  contribution  which  political  economy  has  yet  received  from  America, 
but  it  is  not  too  much  to  say  that  in  these  respects  it  has  had  no  equal  since  the 
publication  of  '  The  Wealth  of  Nations,'  by  Adam  Smith,  a  century  ago,  or,  at 
least,  since  Malthus  formulated  his  theory  of  population  and  Ricardo  his  theory  of 
rent.  A  more  aggressive,  not  to  say  audacious,  book  was  never  written." — New 
York  Herald. 

"  His  book  must  be  accounted  the  first  adequate  presentation  in  the  English 
language  of  that  new  economy  which  has  found  powerful  champions  in  the  Ger- 
man universities,  and  which  aims  at  a  radical  transformation  of  the  science  for- 
mulated by  Adam  Smith,  Ricardo,  and  J.  S.  Mill.  Few  books  have,  in  recent  years, 
proceeded  from  any  American  pen  which  have  more  plainly  borne  the  marks  of 
wide  learning  and  strenuous  thought,  or  which  have  brought  to  the  expounding  of 
a  serious  theme  a  happier  faculty  of  elucidation." — Neio  York  Sun. 

THE  PRINCIPLES  OF  THE  LAW.  An  Examination  of  the  Law  of 
Personal  Rights,  to  Discover  the  Principles  of  the  Law,  as  ascertained  from 
the  Practical  Rules  of  the  Law,  and  harmonized  with  the  Nature  of  Social 
Relations.     By  A.  J.  Willard.     8vo.     Cloth,  $2.50. 

"  This  is  a  philosophical  and  logical  book,  peculiarly  appealing  to  scholars  or 
lawyers  who  love  to  linger  rather  with  legal  cause  and  worldly  effect  than  reported 
cases  or  legal  principles  applied  to  events.  The  author  was  formerly  a  member  of 
the  New  York  bar,  and  lately  Chief-Justice  of  South  Carolina." — New  York  World. 

"  The  author  takes  the  practical  rules  as  they  exist ;  he  concerns  himself  only 
with  their  motive  and  harmony.  He  aims  at  treating  Jurisprudence  somewhat  as 
Emerson,  Darwin,  Spencer  have  written  on  ethics,  nature,  society." — New  York 
Times. 

CAPITAL  AND  POPULATION.  A  Study  of  the  Economic  Effects  of  their 
Relations  to  Each  Other.     By  Frederick  B.  IIawley.     12mo.     Cloth,  $1.50. 

"  It  would  be  false  modesty  in  me  to  seem  unaware  that  the  economit;  law  I 
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hitherto  ascertained.  Granted  its  truth,  it  throws  new  and  decisive  light  on  nearly 
all  the  unsolved  problems  of  the  science." — Extract  from  Preface. 

HERBERT  SPENCER  ON  THE  AMERICANS,  AND  THE 
AMERICANS  OxN  HERBERT  SPENCER.  Being  a  full  Report  of 
his  Interview,  and  of  the  Proceedings  at  the  Farewell  Banquet  (November  9, 
1882),  with  the  Speeches  of  Evarts,  Spencer,  Sumner,  Schurz,  Marsh,  Fiske, 
and  Beecher,  carefully  revised  by  their  authors.  r2mo.  Thick  paper,  25 
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/—    —         -  ■     -  '  ■  '  ■  ■  ^ 

ROSCOE'S    CHEMISTRY— Part  II  of  Volume  III. 

A  Treatise  on  Chemistry.  By  H.  E.  Roscoe,  F.  R.  S.,  and  C.  Schorlemmer, 
F.  R.  S.,  Professors  of  Chemistry  in  the  Victoria  University,  Owens  Col- 
lege, Manchester.    Volmiie  III — Part  II,    The  Chemistry  of  the  IIydro- 

CA.RB0NS   AND    THEIR  DeRIYATIYES,    OR   ORGANIC    CHEMISTRY.       8V0,    cloth, 

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Academy. 

ELE3IEXTS  OF  CHEMISTRY.  By  Professor  F.  W.  Clarke,  Chemist 
of  the  United  States  Geological  Survey.  (Appletons'  Science  Text-Books.) 
12mo,  cloth,  $1.50. 

"  The  author  in  this  text-book  presents  the  difficulties  of  chemical  science  to 
elementary  students  progressively,  and  has  so  arranged  the  helps  in  the  text  and 
notes  that  those  who  have  to  study  without  a  teacher  can  readily  make  certain 
progress.  To  those  who  study  the  science  as  a  part  of  their  general  education, 
and  apply  it  merely  to  the  evcry-day  applications  of  life,  this  book  will  be  found 
amply  complete.  To  such  as  seek  an  advanced  course  of  technical  chemical  train- 
ing, this  work  will  serve  as  a  sound,  scientific  basis  for  higher  study.  The  experi- 
ments cited  are  simple,  and  can  be  readily  performed  by  the  student  himself  with 
apparatus  and  materials  easily  secured.  The  questions  and  exercises  at  the  end 
of  the  book  are  not  exhaustive,  but  suggestive  and  stimulating  to  further  investiga- 
tion. The  book  is  divided  into  two  parts,  Inorganic  and  Organic  Chemistry.  An 
appendix  gives  a  comparative  table  of  English  and  metric  tables,  etc." — Boston 
Journal  of  Education. 

TEXT-BOOK     OF     SYSTEMATIC     MINERAI.OGY.       By   Hilary 
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TEXT-BOOK    OF    DESCRIPTIVE    MINERALOGY,      By  Hilary 

Bauerman,  F.  G.S.,  Associate  of  the  Royal  School  of  Mines.     IGmo,  cloth, 

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A  PHYSICAL  TREATISE  ON  ELECTRICITY  AND  MAGNET- 
ISM. Bj  J.  E.  H.  GoEDOX,  B.  A.  Camb.,  Member  of  the  International 
Congress  of  Electricians,  Paris,  1881 ;  Manager  of  the  Electric  Light 
Department  of  the  Telegraph  Construction  and  Maintenance  Company. 
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language — which  covers  quite  the  same  ground.  It  records  the  most  recent  ad- 
vances in  the  experimental  treatment  of  electrical  problems,  it  describes  with 
minute  carefulness  the  instruments  and  methods  in  use  in  physical  laboratories 
and  is  prodigal  of  beautifully  executed  diagrams  and  drawings  made  to  scale." — 
London  Times. 

"  The  fundamental  point  in  the  whole  work  is  its  perfect  reflection  of  all  that 
is  best  in  the  modern  modes  of  regarding  electric  and  magnetic  forces,  and  in  the 
modern  methods  of  constructing  electrical  instruments." — Engineering. 

A  PRACTICAL  TREAT!:JE  ON  ELECTRIC  LIGHTING.     Bj  J. 

E.  H.  GoEDON,  author  of  "  A  Physical  Treatise  on  Electricity  and 
Magnetism  " ;  Member  of  the  Paris  Congress  of  Electricians.  With 
Twenty-three  full-page  Plates,  and  numerous  Illustrations  in  the  Text. 
8vo.     Cloth,  $4.50. 

"  This  work  has  been  in  preparation  for  some  two  years,  and  has  been  modified 
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might  indicate  the  state  of  that  science  very  nearly  up  to  the  present  date." — From 
Preface. 

THE    MODERN   APPLICATIONS   OF    ELECTRICITY.      By   E. 

IIospiTALiEE.  New  edition,  revised,  with  many  Additions.  Trans- 
lated by  JuLiTJS  Maiee,  Ph.  D. 

Vol.    I.  Electeio  Gexeeatoes,  Electeic  Light. 

Vol.  II.  Telephoxe  :  Various  Applications,  Electrical  Transmission  of 
Energy.     Two  volumes,  8vo.    With  numerous  Illustrations.     $8.00. 

"  M.  Hospitaller  distinguishes  three  sources  of  electricity,  namely,  the  decom- 
position of  metals  or  other  decomposable  bodies  in  acid  or  alkaline  solutions,  the 
transformation  of  heat  into  electrical  energy,  and  lastly  the  conversion  of  work 
into  current — giving  rise  to  the  three  specific  modes  of  force  styled  respectively 
galvanism,  thermo-electricity,  and  dynamic  electricity.  He  gives  a  history  of  the 
progress  of  each,  from  the  first  crude  constructions  of  the  pioneer  to  the  latest  and 
most  perfect  form  of  battery,  thus  furnishing  the  student  of  science  with  a  suffi- 
ciently copious  text-book  of  the  subject,  while  at  the  same  time  affording  to  the 
electrical  engineer  a  valuable  encyclopaedia  of  his  profession.  The  work  presents 
a  most  useful  and  thorough  compendium  of  the  principles  and  practice  of  electrical 
engineering,  written  as  only  an  expert  can  write,  to  whom  the  abstruse  by  long 
study  has  become  simple.  The  translator  has  acted  the  part  of  an  editor  also,  and 
has  added  considerable  material  of  value  to  the  original  text," — Xeio  York  Times, 


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THE  ELECTRIC  LIGHT:  ITS  IIISTOPwY,  PPwODUCTION",  AND 
APPLICATIONS.  By  Em.  Alolave  and  J.  Poulard.  Translated 
from  the  French  hy  T.  O'Conor  Sloane.  Edited,  with  Notes  and 
Additions,  by  C.  M.  Lungren.  With  250  Illustrations.  8vo.  Cloth, 
$5.00. 

"Not  one  of  the  recent  scientific  publications  was  more  needed  or  is  more 
likely  to  be  eagerly  welcomed  than  a  clear,  exhaustive,  and  authoritative  accoimt 
of  the  application  of  electricity  to  the  production  of  light.  We  are  indebted  to 
Messrs.  Appleton  for  issuing,  in  a  large  volume  of  450  pages,  illustrated  with 
several  hundred  woodcuts,  an  English  translation  of  the  well-known  treatise  by 
MM.  Alglave  and  Boulard." — New  York  Sun. 

ELECTRICITY  AND  MAGNETISM.  By  Fleemixg  Jenkin,  Pro- 
fessor of  Engineering  in  the  University  of  Edinburgh.  Illustrated, 
and  Index.  With  Appendix  on  the  Telephone  and  Microphone. 
12mo.     Cloth,  $1.50. 

"  The  plan  followed  in  this  book  is  as  follows :  First,  a  general  svnthetical  view 
of  the  science  has  been  given,  in  which  the  main  phenomena  are  described  and 
the  terms  employed  explained.  If  this  portion  of  the  work  can  be  mastered,  the 
student  will  then  be  re?dily  able  to  understand  what  follows,  viz.,  the  description 
of  the  apparatus  used  to  measure  electrical  magnitudes  and  to  produce  electricity 
imder  various  conditions.  The  general  theory  of  electricity  is  permanent,  depend- 
ing on  no  hypothesis,  and  it  has  been  the  author's  aim  to  state  this  general  theory 
in  a  connected  manner,  and  in  such  simple  form  that  it  might  be  readily  under- 
stood by  practical  men." — Frorn  the  Introduction. 

ELEMENTARY    TREATISE     ON     NATURAL    PHILOSOPHY. 

By  A.  Peivat  Deschanel,  formerly  Professor  of  Physics  in  the  Lycee 
Louis-le-Grand,  Inspector  of  the  Academy  of  Paris.  Translated  and 
edited,  with  Extensive  Modifications,  by  J.  D.  Everett,  Professor  of 
Natural  Philosophy  in  the  Queen's  College,  Belfast.  Sixth  edition, 
revised,  complete  in  Fonr  Parts.  Illustrated  hy  783  Engravings  on 
Wood,  and  Three  Colored  Plates. 

Part     I.  Mechanics,  Hydeostatics,  a;s-d  Pneumatics.     Cloth,  $1.50. 

Part    II.  Heat.     Cloth,  $1.50. 

Part  III.  Electricity  and  Magnetism.     Cloth,  $1.50. 

Part  lY.  Sound  and  Light.     Cloth,  $1.50. 

Complete  in  one  volume,  8vo,  with  Problems  and  Index.    Cloth,  $5.70. 

"  Systematically  arranged,  clearly  written,  and  admirably  illustrated,  showing 
no  less  than  783  engravings  on  wood  and  three  colored  plates,  it  forms  a  model 
work  for  a  class  of  experimental  physics.  Far  from  losing  in  its  English  dress 
any  of  the  qualities  of  matter  or  style  which  distinguished  it  in  its  original  form, 
it  may  be  said  to  have  gained  in  the  able  hands  of  Professor  Everett,  both  by  way 
of  arrangement  and  of  incorporation  cf  fresh  matter,  without  parting  in  the  trans- 
lation with  any  of  the  freshness  or  force  of  the  author's  tcxt.^^  — Sat ur da y  Review. 


New  York :  D.  APPLETON  &  CO.,  1,  3,  &  5  Bond  Street. 


D.  APPLETON  &   CO/S   PUBLICATIONS. 

BRAIN  EXHAUSTION,  WITH  SOME  PRELIMINAEY  CONSID- 
ERATIONS ON  CEREBRAL  DYNAMICS.  By  J.  Leoxaed  Coen- 
iXG,  M.  D.,  formerly  Resident  Physician  to  the  Hudson  River  State 
Hospital  for  the  Insane.     Crown  8vo,  cloth,  $2.00. 

"  The  author  begins  by  laying  a  broad  foundation  for  his  deductions  in  con- 
sidering the  law  of  the  convertibility  of  forces  to  the  dynamics  of  tiie  brain.  This 
parallelism  between  inanimate  physics  and  cerebral  action  is  closely  followed  by 
our  author,  and  with  excellent  results.  Dr.  Corning  proceeds  to  classify  his  facts, 
which  appear  to  be  drawn  from  wide  experience  and  study,  and  to  marshal  them 
■with  the  skill  of  a  trained  scientist.  He  first  considers  the  various  existing  causes 
which  conduce  to  brain  exhaustion  in  the  physical  sense,  such  as  alcohol-drinking, 
tobacco,  excessive  sexualism,  irregular  hours,  etc. ;  in  the  mental  sense,  overwork, 
whether  in  study  and  business,  fret  and  worry,  false  educational  methods,  etc. 
lie  concludes  with  a  summary  of  the  principles  of  brain  hygienics,  and  indicates 
very  clearly  how  brain  exhaustion  may  be  remedied  before  the  final  and  inevitable 
result  comes.  In  these  latter  chapters  the  author  discusses  the  relation  of  blood 
to  muscle  and  brain,  the  relation  of  food  to  mental  phenomena,  rest,  special  medi- 
cation, etc.  The  book  is  admirably  written.  The  style  is  simple,  direct,  lucid,  with 
as  much  avoidance  as  possible  of  technical  terms  and  purely  professional  logic. 
It  is  a  timely  work,  which  every  thinking  man  can  read  with  interest  without  being 
a  physician.  Crain-workcrs  everywhere  can  study  this  able  digest  with  both  profit 
and  pleasure." — Eclectic  Magazine. 

OUTLINES  OF  PSYCHOLOGY,  WITH  SPECIAL  REFERENCE 
TO  THE  THEORY  OF  EDUCATION.  A  Text-Book  for  Colleges. 
By  elAMEs  Sully,  A.  M.,  Examiner  for  the  Moral  Sciences  Tripos  in 
the  University  of  Cambridge,  etc.,  etc.     Crown  8vo,  cloth,  $3.00. 

"  A  book  that  has  been  long  wanted  by  all  who  are  engaged  in  the  business  of 
teaching  and  desire  to  master  its  principles.  In  the  first  place,  it  is  an  elaborate 
treatise  on  the  human  mind,  of  independent  merit  as  representing  the  latest  and 
best  work  of  all  schools  of  psychological  inquiry.  But  of  equal  importance,  and 
what  will  be  prized  as  a  new  and  most  desirable  feature  of  a  work  on  mental  sci- 
ence, is  the  educational  applications  that  are  made  throughout  in  separate  text 
and  type,  so  that,  with  the  explication  of  mental  phenomena,  there  comes  at  once 
the  appUcation  to  the  art  of  education." 

BODY  AND  WILL:  BEING  AN  ESSAY  CONCERNING  WILL  IN 
ITS  METAPHYSICAL,  PHYSIOLOGICAL,  AND  PATHOLOGI- 
CAL ASPECTS.     By  Hexry  Maudsley,  M.  D.     8vo,  cloth,  $2.50. 

"  Dr.  Maudsley's  powers  of  logic  have  never  been  more  keenly  exercised  than 
in '  Body  and  Will,'  his  latest  volume.  He  takes  the  ultra-materialistic  view  of  the 
human  mind,  and  regards  will  as  the  result  of  definite  material  causes,  so  that, 
were  synthetical  science  a  little  further  advanced,  it  w'ould  be  possible,  having 
given  physical  conditions,  to  declare  the  inevitable  result.  The  skill  and  erudition 
displayed  in  '  Body  and  Will '  are  only  equaled  by  the  keenness  of  its  criticisms 
upon  what,  from  the  writer's  point  of  view,  are  empirical  dogmas.  No  fairer  or 
more  able  exposition  on  the  latest  scientific  teaching  upon  the  subject  of  man  as 
a  free  agent  is  to  be  found  than  in  this  volume." — Boston  Courier, 


New  York:  D,  APPLETON  &  CO.,  1,  3,  &  5  Bond  Street 


D.  APPLETON  &   CO:S   PUBLICATIONS. 

DARWINISM  STATED  BY  DARWIN  HIMSELF:  CIIAKAC- 
TERISTIO  PASSAGES  FPwOM  THE  WRITINGS  OF  CHARLES 
DARWIN".  Selected  and  arranged  by  Rrofessor  Natuan  Suei»pard. 
12nio,  cloth,  3G0  pages,  $1.50. 

"A  compact  and  clear  statement  of  the  doctrines  collectively  known  as  Dar- 
winism. By  consulting  this  single  volume  it  is  now  possible  to  know  exactly  wliat 
Darwin  taught  without  sifting  the  contents  of  a  dozen  books.  Mr.  Nathan  Shep- 
pard  has  edited  tlic  work  with  good  judgment." — New  York  Journal  of  Commerce. 

"  Mr.  Sheppard  must  be  credited  with  exemplifying  the  spirit  of  impartial 
truth-seeking  which  inspired  Darwin  himself.  From  these  condensed  results  of 
the  hard  labor  of  selection,  excision,  and  arrangement  applied  to  more  than  a 
dozen  volumes,  it  is  impossible  to  draw  any  inference  respecting  the  philosophical 
opinions  of  the  compiler.  With  the  exception  of  a  brief  preface  there  is  not  a 
word  of  comment,  nor  is  there  the  faintest  indication  of  an  attempt  to  infuse  into 
Darwin's  text  a  meaning  not  patent  there,  b}'  unwarranted  sub-titles  or  head-lines, 
by  shrewd  omission,  unfair  emphasis,  or  artful  collocation.  Mr.  Sheppard  has 
nowhere  swerved  from  his  purpose  of  showing  in  a  clear,  connected,  and  very 
compendious  form,  not  what  Darwin  may  have  meant  or  has  been  charged  with 
meaning,  but  what  he  actually  said." — 7 he  Su7i. 

MENTAL.  EVOLUTION  IN  ANIMALS.  By  George  J.  Romanes, 
author  of  "Animal  InteUigence."  With  a  Posthumous  Essay  on  In- 
stinct, by  Charles  Darwin.     12mo,  cloth,  $2.00. 

"  Mr.  Romanes  has  followed  up  his  careful  enumeration  of  the  facts  of  '  Animal 
Intelligence,'  contributed  to  the  '  International  Scientific  Series,'  with  a  work  deal- 
ing with  the  successive  stages  at  which  the  various  mental  phenomena  appear  in 
the  scale  of  life.  The  present  installment  displays  the  same  evidence  of  industry 
in  collecting  facts  and  caution  in  co-ordinating  them  by  theory  as  the  former." — 
The  Alhenceum. 

"  The  author  confines  himself  to  the  psychology  of  the  subject.  Not  only  are 
his  own  views  Darwinian,  but  he  has  incorporated  in  his  work  considerable  cita- 
tions from  Darwin's  unpublished  manuscripts,  and  he  has  appended  a  posthumous 
essay  on  Instinct  by  Mr.  Darwin." — Boston  Journal. 

"A  curious  but  richly  suggestive  volume." — Kciu  York  Herald. 

PRACTICAL  ESSAYS.  By  Alexander  Bain,  LL.  D.,  author  of  "  Mind 
and  Body,"  "Education  as  a  Science,"  etc.     12mo,  cloth,  $1.50. 

"  The  present  volume  is  in  part  a  reprint  of  articles  contributed  to  reviews. 
The  principal  bond  of  union  among  them  is  their  practical  character.  .  .  .  That 
there  is  a  certain  amount  of  novelty  in  the  various  sujrgestions  here  embodied,  will 
be  admitted  on  the  most  cursory  perusal." — From  the  Preface. 

THE  ESSENTIALS  OF  ANATOxMY,  PHYSIOLOGY,  AND  HY- 
GIENE. By  Roger  S.  Tracy,  M.  D.,  Health  Inspector  of  the  New- 
York  Board  of  Health  ;  author  of  "  Hand-Book  of  Sanitary  Informa- 
tion for  Householders,"  etc.  (Forming  a  volume  of  Appletons'  Sci- 
ence Text-Books.)     12mo,  cloth,  $1.25. 

"  Dr.  Tracy  states  in  his  preface  that  his  aim  has  been  '  to  compress  within  the 
narrowest  space  such  a  clear  and  intelligible  account  of  the  structures,  activities, 
and  care  of  the  human  system  as  is  essential  for  the  purposes  of  general  educa- 
tion.' And  he  has  so  far  succeeded  as  to  make  his  manual  one  of  the  most 
popularly  interesting  and  useful  text-books  of  its  kind.  .  .  .  The  book  is  excel- 
lently arranged,  the  illustrations  are  adntirable." — Boston  Daily  Advertiser. 

New  York:  D.  APPLETON  &  CO.,  1,  3,  &  5  Bond  Street. 


THE 

POPULAR  SCIENCE  MONTHLY. 

CONDUCTED  BY  E.  L  AND   W.  J.   YOUMANS. 


The  Popular  Sciexce  Monthly  will  continue,  as  heretofore,  to  sup- 
]>ly  its  readers  with  the  results  of  the  latest  investigation  and  the  most 
valuable  thought  in  the  various  departments  of  scientific  inquiry. 

Leaving  the  dry  and  technical  details  of  science,  which  are  of  chief 
concern  to  specialists,  to  the  journals  devoted  to  them,  the  Monthly 
deals  with  those  more  general  and  practical  subjects  which  are  of  the 
greatest  interest  and  importance  to  the  public  at  large.  In  this  work  it 
has  achieved  a  foremost  position,  and  is  now  the  acknowledged  organ  of 
progressive  scientific  ideas  in  this  country. 

The  wide  range  of  its  discussions  includes,  among  other  topics: 

The  bearing  of  science  upon  education; 

Questions  relating  to  the  prevention  of  disease  and  the  improvement 
of  sanitary  conditions ; 

Subjects  of  domestic  and  social  economy,  including  the  introduction 
of  better  ways  of  living,  and  improved  applications  in  the  arts  of  every 
kind  ; 

The  phenomena  and  laws  of  the  larger  social  organizations,  with  the 
new  standard  of  ethics,  based  on  scientific  principles; 

The  subjects  of  personal  and  household  hygiene,  medicine,  and  archi- 
tecture, as  exemplified  in  the  adaptation  of  public  buildings  and  private 
houses  to  the  wants  of  those  who  use  them ; 

Agriculture  and  the  improvement  of  food  products; 

The  study  of  man,  with  what  appears  from  time  to  time  in  the  depart- 
ments of  anthropology  and  archaeology  that  may  throw  light  upon  the 
development  of  the  race  from  its  primitive  conditions. 

"Whatever  of  real  advance  is  made  in  chemistry,  geography,  astrono- 
my, physiology,  psychology,  botany,  zoology,  paleontology,  geology,  or 
such  other  department  as  may  have  been  the  field  of  research,  is  recorded 
monthly. 

Special  attention  is  also  called  to  the  biographies,  with  portraits,  of 
representative  scientific  men,  in  which  are  recorded  their  most  marked 
achievements  in  science,  and  the  general  bearing  of  their  work  indicated 
and  its  value  estimated. 

Terms :  ^5.00  per  Annum,  in  advance. 

The  New  York  Medical  Journal  and  The  Popular  Science  Monthly  to 
the  same  address,  S9.00  per  Annum  (full  price,  SIO.OO). 


New  York :  D.  APPLETOX  &  CO.,  1,  3,  &  5  Bond  Street. 


